Pub Date : 2024-09-29DOI: 10.1016/j.ssc.2024.115709
E. Krishnamoorthy , R. Mariappan , G. Gowrisankar , R. Bakkiyaraj
The synthesized LiZnPO4 nanoparticles were characterized at different temperatures like (400oC, 500 °C, 600 °C, and 700 °C) using various techniques including XRD, FTIR, FESEM, XPS, and electrochemical analyses. X-ray diffraction (XRD) analysis of LiZnPO4 nanoparticles sintered at temperatures from 400 to 700 °C revealed well-crystallized structures at 700 °C, with preferred orientations along (202) and (020) planes. The Scherrer formula was employed to determine crystallite sizes, showing an increase from 55 nm at 400 °C to 85 nm at 700 °C. The annealing temperature influences the formation of microspherical aggregates, determining their surface area and thereby affecting energy storage performance. Samples annealed at 700 °C exhibited a specific capacitance of approximately 268 F/g at a current density of 0.5 A/g and scan rate of 5 mV/s. Our studies indicate that LiZnPO4-based nanostructures have substantial potential for the development of hybrid supercapacitors.
在不同温度（400℃、500℃、600℃和 700℃）下，使用 XRD、傅立叶变换红外光谱、FESEM、XPS 和电化学分析等多种技术对合成的纳米磷酸锌锂进行了表征。对在 400 至 700 °C 温度下烧结的 LiZnPO4 纳米粒子进行的 X 射线衍射（XRD）分析表明，在 700 °C 温度下结晶结构良好，优先取向为 (202) 和 (020) 平面。利用舍勒公式测定的结晶尺寸显示，结晶尺寸从 400 °C 时的 55 nm 增加到 700 °C 时的 85 nm。退火温度会影响微球形聚集体的形成，决定其表面积，从而影响储能性能。在电流密度为 0.5 A/g 和扫描速率为 5 mV/s 的条件下，在 700 °C 下退火的样品显示出约 268 F/g 的比电容。我们的研究表明，基于 LiZnPO4 的纳米结构具有开发混合超级电容器的巨大潜力。
{"title":"Advancements in lithium zinc phosphate (LZP) nanoparticles: Enhanced electrochemical performance for high-efficiency supercapacitors","authors":"E. Krishnamoorthy , R. Mariappan , G. Gowrisankar , R. Bakkiyaraj","doi":"10.1016/j.ssc.2024.115709","DOIUrl":"10.1016/j.ssc.2024.115709","url":null,"abstract":"<div><div>The synthesized LiZnPO<sub>4</sub> nanoparticles were characterized at different temperatures like (400<sup>o</sup>C, 500 °C, 600 °C, and 700 °C) using various techniques including XRD, FTIR, FESEM, XPS, and electrochemical analyses. X-ray diffraction (XRD) analysis of LiZnPO<sub>4</sub> nanoparticles sintered at temperatures from 400 to 700 °C revealed well-crystallized structures at 700 °C, with preferred orientations along (202) and (020) planes. The Scherrer formula was employed to determine crystallite sizes, showing an increase from 55 nm at 400 °C to 85 nm at 700 °C. The annealing temperature influences the formation of microspherical aggregates, determining their surface area and thereby affecting energy storage performance. Samples annealed at 700 °C exhibited a specific capacitance of approximately 268 F/g at a current density of 0.5 A/g and scan rate of 5 mV/s. Our studies indicate that LiZnPO<sub>4</sub>-based nanostructures have substantial potential for the development of hybrid supercapacitors.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115709"},"PeriodicalIF":2.1,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-28DOI: 10.1016/j.ssc.2024.115699
Abu Bakar , A. Afaq , Muhammad Ahmed , Zahoor Ahmad , Shahid M. Ramay
This study reports the first-principles investigations of flouroperovskites, TlXF3(X Ca, Cd), within the frame work of Density Functional Theory. A comprehensive and improved data of flouroperovskites on structural, phonon, elasto-mechanical, optoelectronic and thermoelectric properties are carried out using Perdew Burke Ernzerhof-Generalized Gradient Approximation (PBE-GGA), Trans-Blaha modified Becke–Johnson (TB-mBJ), meta GGA, Strongly Constrained and Appropriately Normed (SCAN), hybrid functional including Becke’s three parameter exchange functional with the Lee–Yang–Parr (B3LYP) and range-separated hybrid functional Heyd–Scuseria–Ernzerhof (HSE06). The structures are optimized and stability is proved by energy-volume optimization, formation energy calculations, positive phonon frequencies of phonon dispersion curves and elastic constant criteria. The electronic band structures of both TlCaF3 and TlCdF3 possess direct and indirect nature respectively and density of states are consistent with electronic band structure. The band gaps of TlCaF3 are 4.53 eV (PBE-GGA), 6.19 eV (TB-mBJ), 4.89 eV (SCAN), 6.24 eV (B3LYP) and 5.98 eV (HSE06) and the band gaps of TlCdF3 are 3.74 eV (PBE-GGA), 5.64 eV (TB-mBJ), 4.30 eV (SCAN), 5.83 eV (B3LYP) and 5.53 eV (HSE06). The dynamical stability and brittle response of TlCaF3 and TlCdF3 is confirmed from shear constant, Pugh’s ratio and Poisson’s ratio. The optical and thermoelectric response are studied for optoelectronic and sustainable applications.
本研究报告了在密度泛函理论框架内对 TlXF3（X = Ca、Cd）氟软玉的第一性原理研究。元 GGA、强约束和适当规范化（SCAN）、混合函数（包括贝克的三参数交换函数和李-杨-帕尔（B3LYP））以及范围分离混合函数 Heyd-Scuseria-Ernzerhof (HSE06)）。通过能量-体积优化、形成能计算、声子频散曲线的正声子频率和弹性常数标准对结构进行了优化，并证明了其稳定性。TlCaF3 和 TlCdF3 的电子带结构分别具有直接和间接性质，其态密度与电子带结构一致。TlCaF3 的带隙分别为 4.53 eV（PBE-GGA）、6.19 eV（TB-mBJ）、4.89 eV（SCAN）、6.24 eV（B3LYP）和 5.98 eV (HSE06)，而 TlCdF3 的带隙分别为 3.74 eV (PBE-GGA)、5.64 eV (TB-mBJ)、4.30 eV (SCAN)、5.83 eV (B3LYP) 和 5.53 eV (HSE06)。剪切常数、普氏比和泊松比证实了 TlCaF3 和 TlCdF3 的动态稳定性和脆性响应。研究了光电和热电响应，以促进光电和可持续应用。
{"title":"Revealing the remarkably improved structural, phonon, elastic, optoelectronic and thermoelectric properties of TlXF3(X = Ca, Cd) for energy applications using first-principles approach with hybrid and range-separated hybrid functionals","authors":"Abu Bakar , A. Afaq , Muhammad Ahmed , Zahoor Ahmad , Shahid M. Ramay","doi":"10.1016/j.ssc.2024.115699","DOIUrl":"10.1016/j.ssc.2024.115699","url":null,"abstract":"<div><div>This study reports the first-principles investigations of flouroperovskites, TlXF<sub>3</sub>(X <span><math><mo>=</mo></math></span> Ca, Cd), within the frame work of Density Functional Theory. A comprehensive and improved data of flouroperovskites on structural, phonon, elasto-mechanical, optoelectronic and thermoelectric properties are carried out using Perdew Burke Ernzerhof-Generalized Gradient Approximation (PBE-GGA), Trans-Blaha modified Becke–Johnson (TB-mBJ), meta GGA, Strongly Constrained and Appropriately Normed (SCAN), hybrid functional including Becke’s three parameter exchange functional with the Lee–Yang–Parr (B3LYP) and range-separated hybrid functional Heyd–Scuseria–Ernzerhof (HSE06). The structures are optimized and stability is proved by energy-volume optimization, formation energy calculations, positive phonon frequencies of phonon dispersion curves and elastic constant criteria. The electronic band structures of both TlCaF<sub>3</sub> and TlCdF<sub>3</sub> possess direct and indirect nature respectively and density of states are consistent with electronic band structure. The band gaps of TlCaF<sub>3</sub> are 4.53 eV (PBE-GGA), 6.19 eV (TB-mBJ), 4.89 eV (SCAN), 6.24 eV (B3LYP) and 5.98 eV (HSE06) and the band gaps of TlCdF<sub>3</sub> are 3.74 eV (PBE-GGA), 5.64 eV (TB-mBJ), 4.30 eV (SCAN), 5.83 eV (B3LYP) and 5.53 eV (HSE06). The dynamical stability and brittle response of TlCaF<sub>3</sub> and TlCdF<sub>3</sub> is confirmed from shear constant, Pugh’s ratio and Poisson’s ratio. The optical and thermoelectric response are studied for optoelectronic and sustainable applications.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115699"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-28DOI: 10.1016/j.ssc.2024.115707
Yves Noat , Alain Mauger , William Sacks
<div><div>Thermal measurements, such as entropy and specific heat, reveal key elementary excitations for understanding the cuprates. In this paper, we study the specific heat measurements on three different compounds La<span><math><msub><mrow></mrow><mrow><mn>2</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Sr<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>CuO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>, Bi<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Sr<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>CaCu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>8</mn><mo>+</mo><mi>δ</mi></mrow></msub></math></span> and YBa<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Cu<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>7</mn><mo>−</mo><mi>δ</mi></mrow></msub></math></span> and show that the data are compatible with ‘pairons’ and their excitations. However, the precise fits require the contribution of the antiferromagnetic entropy deduced from the magnetic susceptibility <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>.</div><div>Two temperature scales are involved in the excitations above the critical temperature <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>: the pseudogap <span><math><msup><mrow><mi>T</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span>, related to pairon excitations, and the magnetic correlation temperature, <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math></span>, having very different dependencies on the carrier density (<span><math><mi>p</mi></math></span>). In agreement with our previous analysis of <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>, the <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub><mrow><mo>(</mo><mi>p</mi><mo>)</mo></mrow></mrow></math></span> line is not the signature of a gap in the electronic density of states, but is rather the temperature scale of strong local antiferromagnetic correlations which dominate for low carrier concentration. These correlations progressively evolve into paramagnetic fluctuations in the overdoped limit.</div><div>Our results are in striking contradiction with the model of Tallon and Storey (2023), who reaffirm the idea of a <span><math><mi>T</mi></math></span>-independent gap <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>g</mi></mrow></msub></math></span>, whose temperature scale <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>=</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>/</mo><msub><mrow><mi>k</mi></mrow><mrow><mi>B</mi
{"title":"Unraveling pairon excitations and the antiferromagnetic contributions in the cuprate specific heat","authors":"Yves Noat , Alain Mauger , William Sacks","doi":"10.1016/j.ssc.2024.115707","DOIUrl":"10.1016/j.ssc.2024.115707","url":null,"abstract":"<div><div>Thermal measurements, such as entropy and specific heat, reveal key elementary excitations for understanding the cuprates. In this paper, we study the specific heat measurements on three different compounds La<span><math><msub><mrow></mrow><mrow><mn>2</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Sr<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>CuO<span><math><msub><mrow></mrow><mrow><mn>4</mn></mrow></msub></math></span>, Bi<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Sr<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>CaCu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>8</mn><mo>+</mo><mi>δ</mi></mrow></msub></math></span> and YBa<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Cu<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>7</mn><mo>−</mo><mi>δ</mi></mrow></msub></math></span> and show that the data are compatible with ‘pairons’ and their excitations. However, the precise fits require the contribution of the antiferromagnetic entropy deduced from the magnetic susceptibility <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>.</div><div>Two temperature scales are involved in the excitations above the critical temperature <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>: the pseudogap <span><math><msup><mrow><mi>T</mi></mrow><mrow><mo>∗</mo></mrow></msup></math></span>, related to pairon excitations, and the magnetic correlation temperature, <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math></span>, having very different dependencies on the carrier density (<span><math><mi>p</mi></math></span>). In agreement with our previous analysis of <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>, the <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub><mrow><mo>(</mo><mi>p</mi><mo>)</mo></mrow></mrow></math></span> line is not the signature of a gap in the electronic density of states, but is rather the temperature scale of strong local antiferromagnetic correlations which dominate for low carrier concentration. These correlations progressively evolve into paramagnetic fluctuations in the overdoped limit.</div><div>Our results are in striking contradiction with the model of Tallon and Storey (2023), who reaffirm the idea of a <span><math><mi>T</mi></math></span>-independent gap <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>g</mi></mrow></msub></math></span>, whose temperature scale <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>=</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>/</mo><msub><mrow><mi>k</mi></mrow><mrow><mi>B</mi","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115707"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-28DOI: 10.1016/j.ssc.2024.115708
Zhenbo Wang , Pei Liu , Aiqin Wang , Jingpei Xie , Bo Hou , Feng Ye
In the present work, using pre-alloyed Ti-48Al-2Cr-2Nb powders and graphite powders with different contents as raw materials, the Ti2AlC/TiAl composites with network architecture were fabricated by spark plasma sintering (SPS). The effect of carbon content on the microstructure and mechanical properties of Ti2AlC/TiAl composites with network architecture was investigated. The results have shown that with the increasing carbon content from 0.5 wt% to 2 wt%, the network continuity of Ti2AlC particles gradually transforms from semi-continuous network into quasi-continuous and nearly-continuous network, and the network thickness transforms from 5 to 10 μm into 10∼15 μm and 20∼30 μm. The Ti2AlC/TiAl composite with 1 wt% C shows a better balance of compressive strength and ductility, which the room-temperature compressive strength is 2051 MPa and compressive strain is 30.9 %. The quasi-continuous network structural Ti2AlC particles in Ti2AlC/TiAl composite with 1 wt% C could effectively deplete the crack propagation energy by deflecting the crack, and passivate the crack to hinder further propagation, which facilitates the improvement of the strength and ductility in the Ti2AlC/TiAl composite.
{"title":"Effect of carbon content on the microstructure and mechanical properties of Ti2AlC/TiAl composites with network architecture","authors":"Zhenbo Wang , Pei Liu , Aiqin Wang , Jingpei Xie , Bo Hou , Feng Ye","doi":"10.1016/j.ssc.2024.115708","DOIUrl":"10.1016/j.ssc.2024.115708","url":null,"abstract":"<div><div>In the present work, using pre-alloyed Ti-48Al-2Cr-2Nb powders and graphite powders with different contents as raw materials, the Ti<sub>2</sub>AlC/TiAl composites with network architecture were fabricated by spark plasma sintering (SPS). The effect of carbon content on the microstructure and mechanical properties of Ti<sub>2</sub>AlC/TiAl composites with network architecture was investigated. The results have shown that with the increasing carbon content from 0.5 wt% to 2 wt%, the network continuity of Ti<sub>2</sub>AlC particles gradually transforms from semi-continuous network into quasi-continuous and nearly-continuous network, and the network thickness transforms from 5 to 10 μm into 10∼15 μm and 20∼30 μm. The Ti<sub>2</sub>AlC/TiAl composite with 1 wt% C shows a better balance of compressive strength and ductility, which the room-temperature compressive strength is 2051 MPa and compressive strain is 30.9 %. The quasi-continuous network structural Ti<sub>2</sub>AlC particles in Ti<sub>2</sub>AlC/TiAl composite with 1 wt% C could effectively deplete the crack propagation energy by deflecting the crack, and passivate the crack to hinder further propagation, which facilitates the improvement of the strength and ductility in the Ti<sub>2</sub>AlC/TiAl composite.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115708"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.ssc.2024.115703
Jia-chen Wang, Di Fan, Wen-qian Chen, Yong Lu
This study investigates the electronic structures, elastic behaviors, and magnetic properties of monolayer NiI in two novel phases, and , using first-principles calculations and Monte Carlo simulations. The electronic structures of and phases show half-metallic properties with spin magnetic moments of 0.85 and 0.82 respectively. Both phases exhibit mechanical and dynamic stability. The phase has isotropic elastic properties and good ductility, while the phase shows significant crystallographic anisotropy. The spin exchange coupling constants between the nearest and the next-nearest neighbor Ni ions in the phase are nearly an order of magnitude higher than those in the phase, with the former having a Curie temperature close to room temperature at 296 K, significantly higher than the 27 K of the latter. The strain modulation range for structural and magnetic phase transitions between the and phases is provided theoretically.
{"title":"Electronic structures, elastic behaviors and magnetic properties of monolayer P3̄m1 and P4/nmm Ni2I2","authors":"Jia-chen Wang, Di Fan, Wen-qian Chen, Yong Lu","doi":"10.1016/j.ssc.2024.115703","DOIUrl":"10.1016/j.ssc.2024.115703","url":null,"abstract":"<div><div>This study investigates the electronic structures, elastic behaviors, and magnetic properties of monolayer Ni<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>I<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> in two novel phases, <span><math><mrow><mi>P</mi><mover><mrow><mn>3</mn></mrow><mrow><mo>̄</mo></mrow></mover><mi>m</mi><mn>1</mn></mrow></math></span> and <span><math><mrow><mi>P</mi><mn>4</mn><mo>/</mo><mi>n</mi><mi>m</mi><mi>m</mi></mrow></math></span>, using first-principles calculations and Monte Carlo simulations. The electronic structures of <span><math><mrow><mi>P</mi><mover><mrow><mn>3</mn></mrow><mrow><mo>̄</mo></mrow></mover><mi>m</mi><mn>1</mn></mrow></math></span> and <span><math><mrow><mi>P</mi><mn>4</mn><mo>/</mo><mi>n</mi><mi>m</mi><mi>m</mi></mrow></math></span> phases show half-metallic properties with spin magnetic moments of 0.85 and 0.82 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> respectively. Both phases exhibit mechanical and dynamic stability. The <span><math><mrow><mi>P</mi><mover><mrow><mn>3</mn></mrow><mrow><mo>̄</mo></mrow></mover><mi>m</mi><mn>1</mn></mrow></math></span> phase has isotropic elastic properties and good ductility, while the <span><math><mrow><mi>P</mi><mn>4</mn><mo>/</mo><mi>n</mi><mi>m</mi><mi>m</mi></mrow></math></span> phase shows significant crystallographic anisotropy. The spin exchange coupling constants between the nearest and the next-nearest neighbor Ni ions in the <span><math><mrow><mi>P</mi><mn>4</mn><mo>/</mo><mi>n</mi><mi>m</mi><mi>m</mi></mrow></math></span> phase are nearly an order of magnitude higher than those in the <span><math><mrow><mi>P</mi><mover><mrow><mn>3</mn></mrow><mrow><mo>̄</mo></mrow></mover><mi>m</mi><mn>1</mn></mrow></math></span> phase, with the former having a Curie temperature close to room temperature at 296 K, significantly higher than the 27 K of the latter. The strain modulation range for structural and magnetic phase transitions between the <span><math><mrow><mi>P</mi><mover><mrow><mn>3</mn></mrow><mrow><mo>̄</mo></mrow></mover><mi>m</mi><mn>1</mn></mrow></math></span> and <span><math><mrow><mi>P</mi><mn>4</mn><mo>/</mo><mi>n</mi><mi>m</mi><mi>m</mi></mrow></math></span> phases is provided theoretically.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115703"},"PeriodicalIF":2.1,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, niobium diboride (NbB2) was investigated using synchrotron radiation X-ray diffraction in a diamond anvil cell to analyze their compressive behavior at room temperature. The volume of the NbB2 was fitted to its corresponding highest pressures of 32.2 GPa without experiencing structural phase transitions, leading to the determination of bulk modulus of 389(7) GPa. Additionally, we further investigated the bulk modulus, band structure and density of states of NbB2 to 35 GPa by density functional theory. The results yielded a bulk modulus of 285 GPa for NbB2. Importantly, it was observed that NbB2 demonstrates both metallic and non-magnetic properties throughout the pressure range. In addition, we studied the deviatoric stress of NbB2 at high pressure using linewidth analysis method. It was found that NbB2 can support a maximum differential stress of 14.2 GPa at the pressure of 17.3 GPa.
{"title":"The physical properties and mechanical behavior of NbB2 at high pressure","authors":"Lun Xiong , Mingquan Jiang , Fang Miao , Sheng Jiang","doi":"10.1016/j.ssc.2024.115706","DOIUrl":"10.1016/j.ssc.2024.115706","url":null,"abstract":"<div><div>In this study, niobium diboride (NbB<sub>2</sub>) was investigated using synchrotron radiation X-ray diffraction in a diamond anvil cell to analyze their compressive behavior at room temperature. The volume of the NbB<sub>2</sub> was fitted to its corresponding highest pressures of 32.2 GPa without experiencing structural phase transitions, leading to the determination of bulk modulus of 389(7) GPa. Additionally, we further investigated the bulk modulus, band structure and density of states of NbB<sub>2</sub> to 35 GPa by density functional theory. The results yielded a bulk modulus of 285 GPa for NbB<sub>2</sub>. Importantly, it was observed that NbB<sub>2</sub> demonstrates both metallic and non-magnetic properties throughout the pressure range. In addition, we studied the deviatoric stress of NbB<sub>2</sub> at high pressure using linewidth analysis method. It was found that NbB<sub>2</sub> can support a maximum differential stress of 14.2 GPa at the pressure of 17.3 GPa.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115706"},"PeriodicalIF":2.1,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The first-principles calculations are employed to investigate the Ce doping effects on the ferroelectricity of the Aurivillius-structured CaBi2Nb2O9 (CBN). The formation energy is calculated for the Ce substituting the Bi site model and the Ce substituting the Ca site model, it is noted that the former is more stable than the latter. The NbO6 octahedron distortion of the Ce/Bi model is increased due to the long-range effect of the Ce doping. By analyzing the partial density of states (PDOS), the Bader charge and the electron localization function (ELF), it is found that the extra electrons are introduced by the Ce doping, and transferred to the atoms of O2, O5, Nb and Bi. Thus, the electronic orbital hybridizations of O2-Nb, O5-Bi, and O2-Bi are enhanced by the extra electrons, and the enhancement of the orbital hybridization is the main reason of the enhancement of the spontaneous polarization (Ps) comparing with intrinsic CBN. These findings could be used as a theoretical reference for future researches on the bismuth layer-structured ferroelectrics (BLSFs).
利用第一性原理计算研究了掺杂 Ce 对 Aurivillius 结构 CaBi2Nb2O9（CBN）铁电性的影响。计算了 Ce 取代 Bi 位点模型和 Ce 取代 Ca 位点模型的形成能，发现前者比后者更稳定。由于掺杂 Ce 的长程效应，Ce/Bi 模型的 NbO6 八面体畸变增大。通过分析部分态密度（PDOS）、Bader 电荷和电子局域函数（ELF），发现掺杂 Ce 后引入了额外的电子，并转移到 O2、O5、Nb 和 Bi 原子上。因此，额外电子增强了 O2-Nb、O5-Bi 和 O2-Bi 的电子轨道杂化，与本征 CBN 相比，轨道杂化的增强是自发极化（Ps）增强的主要原因。这些发现可作为今后研究铋层结构铁电体（BLSFs）的理论参考。
{"title":"Ferroelectricity enhanced by cerium modified CaBi2Nb2O9-based Aurivillius ferroelectrics","authors":"Hong-Ting Lu, Ji-Chao Li, Chun-Ming Wang, Jian Liu, Tian-Ci Wu, Guang-Rui Yang","doi":"10.1016/j.ssc.2024.115705","DOIUrl":"10.1016/j.ssc.2024.115705","url":null,"abstract":"<div><div>The first-principles calculations are employed to investigate the Ce doping effects on the ferroelectricity of the Aurivillius-structured CaBi<sub>2</sub>Nb<sub>2</sub>O<sub>9</sub> (CBN). The formation energy is calculated for the Ce substituting the Bi site model and the Ce substituting the Ca site model, it is noted that the former is more stable than the latter. The NbO<sub>6</sub> octahedron distortion of the Ce/Bi model is increased due to the long-range effect of the Ce doping. By analyzing the partial density of states (PDOS), the Bader charge and the electron localization function (ELF), it is found that the extra electrons are introduced by the Ce doping, and transferred to the atoms of O2, O5, Nb and Bi. Thus, the electronic orbital hybridizations of O2-Nb, O5-Bi, and O2-Bi are enhanced by the extra electrons, and the enhancement of the orbital hybridization is the main reason of the enhancement of the spontaneous polarization (<em>P</em><sub>s</sub>) comparing with intrinsic CBN. These findings could be used as a theoretical reference for future researches on the bismuth layer-structured ferroelectrics (BLSFs).</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115705"},"PeriodicalIF":2.1,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-20DOI: 10.1016/j.ssc.2024.115704
Kaixin Wu , Yuxian Wu , Yong Zhao
We investigated the crystal structure and superconductivity in the FeSe0.94-xSx (x = 0, 0.1) single crystals. Two distinct phases have been detected in both the FeSe0.94 and FeSe0.84S0.1 samples. The critical temperatures and upper critical field were obtained from the temperature dependence of resistivity curves under different magnetic fields. The transport properties of FeSe0.94 and FeSe0.84S0.1 in the mixed state were investigated. The relation between the effective pinning energy U0 and magnetic field was derived within the framework of the thermally activated flux motion model. A power-law relation U0 ∼H−α was observed in the U0 (H) for FeSe0.84S0.1, which shows a crossover behavior around 4 T attributed to different pinning mechanisms. It is demonstrated that S doping significantly influences the critical temperature, effective pinning energy, and upper critical field.
{"title":"Upper critical field and effective pinning energy in FeSe0.94-xSx single crystals","authors":"Kaixin Wu , Yuxian Wu , Yong Zhao","doi":"10.1016/j.ssc.2024.115704","DOIUrl":"10.1016/j.ssc.2024.115704","url":null,"abstract":"<div><div>We investigated the crystal structure and superconductivity in the FeSe<sub>0.94-<em>x</em></sub>S<sub><em>x</em></sub> (<em>x</em> = 0, 0.1) single crystals. Two distinct phases have been detected in both the FeSe<sub>0.94</sub> and FeSe<sub>0.84</sub>S<sub>0.1</sub> samples. The critical temperatures and upper critical field were obtained from the temperature dependence of resistivity curves under different magnetic fields. The transport properties of FeSe<sub>0.94</sub> and FeSe<sub>0.84</sub>S<sub>0.1</sub> in the mixed state were investigated. The relation between the effective pinning energy <em>U</em><sub>0</sub> and magnetic field was derived within the framework of the thermally activated flux motion model. A power-law relation <em>U</em><sub>0</sub> ∼<em>H</em><sup>−</sup><em><sup>α</sup></em> was observed in the <em>U</em><sub>0</sub> (<em>H</em>) for FeSe<sub>0.84</sub>S<sub>0.1</sub>, which shows a crossover behavior around 4 T attributed to different pinning mechanisms. It is demonstrated that S doping significantly influences the critical temperature, effective pinning energy, and upper critical field.</div></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115704"},"PeriodicalIF":2.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.ssc.2024.115700
Sopheap Sam , Kosuke Yamazaki , Hiroshi Nakatsugawa
Understanding the thermal transport behaviors in the crystal lattice is important for designing semiconducting materials in thermal management. In this work, we investigate the mechanism of the decrease in thermal properties of β-FeSi2 when Co dopant is introduced to the host crystal. The crystallite size decreases as Co doping increases from 0 to 5 %. The micro-strain and stress increase with increasing doping levels. The decrease in crystallite size and increase in micro-strain/stress indicate the origin of phonons scattering and lattice softening, leading to the reduction in thermal conductivity. This study provides insights into the correlation between the crystal properties evolution and thermal transport in metal silicide compounds which could be useful in thermal-to-energy conversion applications.
了解晶格中的热传输行为对于设计热管理半导体材料非常重要。在这项工作中，我们研究了当主晶中引入掺杂 Co 时，β-FeSi2 热性能下降的机理。随着钴掺杂量从 0% 增加到 5%，晶体尺寸减小。微应变和应力随着掺杂水平的增加而增加。晶粒尺寸的减小和微应变/应力的增加表明，声子散射和晶格软化是导致热导率降低的原因。这项研究深入揭示了金属硅化物的晶体特性演变与热传输之间的相关性，可用于热能转换应用。
{"title":"Thermal conductivity reduction and crystal properties evolution in iron silicides induced by doping","authors":"Sopheap Sam , Kosuke Yamazaki , Hiroshi Nakatsugawa","doi":"10.1016/j.ssc.2024.115700","DOIUrl":"10.1016/j.ssc.2024.115700","url":null,"abstract":"<div><p>Understanding the thermal transport behaviors in the crystal lattice is important for designing semiconducting materials in thermal management. In this work, we investigate the mechanism of the decrease in thermal properties of β-FeSi<sub>2</sub> when Co dopant is introduced to the host crystal. The crystallite size decreases as Co doping increases from 0 to 5 %. The micro-strain and stress increase with increasing doping levels. The decrease in crystallite size and increase in micro-strain/stress indicate the origin of phonons scattering and lattice softening, leading to the reduction in thermal conductivity. This study provides insights into the correlation between the crystal properties evolution and thermal transport in metal silicide compounds which could be useful in thermal-to-energy conversion applications.</p></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115700"},"PeriodicalIF":2.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.ssc.2024.115701
Bharat Bhardwaj, Rajnish Kurchania
A comprehensive study of lead-free halide double perovskite using density functional theory (DFT) including structural, electronic, dynamical, mechanical, optical, and thermoelectric properties has been carried out. The tolerance factor and the octahedral factor confirm that the compound belongs to face-centred-cubic structure with Fm-3m space group. The predicted band structure and DOS exhibit that the material is an indirect bandgap semiconductor. Our calculation reveals that material is dynamically stable because of no negative frequency found in phonon-dispersion curve. The material also possesses mechanical stability. The optical spectra of material show good absorbance and low reflectivity in ultraviolet region. The thermoelectric part discusses the Seebeck coefficient, thermal conductivity, electrical conductivity, power factor, and figure of merit (zT) at different chemical potential into temperature range 400–1200 K. The purpose of this investigation is to stimulate researchers to develop this kind of material and assess their potential for the advancement of contemporary thermoelectric and optoelectronic devices.
利用密度泛函理论（DFT）对无铅卤化物双包晶进行了全面研究，包括结构、电子、动力学、机械、光学和热电性能。公差因子和八面体因子证实该化合物属于面心立方结构，空间群为 Fm-3m。预测的带状结构和 DOS 显示，该材料是一种间接带隙半导体。我们的计算显示，由于声子色散曲线中没有发现负频率，因此该材料具有动态稳定性。该材料还具有机械稳定性。材料的光学光谱显示出良好的吸收率和紫外区的低反射率。热电部分讨论了在 400-1200 K 温度范围内不同化学势下的塞贝克系数、热导率、电导率、功率因数和优点系数 (zT)。
{"title":"New semiconducting lead-free halide double perovskite Ag2LiGaF6 for optoelectronic and thermoelectric applications","authors":"Bharat Bhardwaj, Rajnish Kurchania","doi":"10.1016/j.ssc.2024.115701","DOIUrl":"10.1016/j.ssc.2024.115701","url":null,"abstract":"<div><p>A comprehensive study of lead-free halide double perovskite using density functional theory (DFT) including structural, electronic, dynamical, mechanical, optical, and thermoelectric properties has been carried out. The tolerance factor and the octahedral factor confirm that the compound belongs to face-centred-cubic structure with Fm-3m space group. The predicted band structure and DOS exhibit that the material is an indirect bandgap semiconductor. Our calculation reveals that material is dynamically stable because of no negative frequency found in phonon-dispersion curve. The material also possesses mechanical stability. The optical spectra of material show good absorbance and low reflectivity in ultraviolet region. The thermoelectric part discusses the Seebeck coefficient, thermal conductivity, electrical conductivity, power factor, and figure of merit (zT) at different chemical potential into temperature range 400–1200 K. The purpose of this investigation is to stimulate researchers to develop this kind of material and assess their potential for the advancement of contemporary thermoelectric and optoelectronic devices.</p></div>","PeriodicalId":430,"journal":{"name":"Solid State Communications","volume":"394 ","pages":"Article 115701"},"PeriodicalIF":2.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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