Pub Date : 2025-12-13DOI: 10.1016/j.cap.2025.12.007
Ann V. Lizbathu , Sajan Thomas , Neekha Deen Abraham , Jifi Jose , Bibily Baby , Ditty Dixon , P.R. Biju , Cyriac Joseph
The evolution of energy storage systems that are less expensive and can perform efficiently is presently required for the modern world. Therefore, supercapacitors that possess unique characteristics including power delivery, fast recharging, and extended cycle life have been attracting lot of interest. In this vein, cerium oxalate decahydrate is considered to be an intriguing material for energy storage due to its structural benefits that can enhance specific capacitance. Electrochemical studies of the material were investigated in redox additive electrolyte, which revealed that the material possesses a battery-type charge storage mechanism. In three-electrode configuration, the material attained a maximum specific capacitance of ∼1667 F/g at 1 A/g. The asymmetric device delivered a specific capacitance of ∼552 F/g and an impressive energy density of ∼150 Wh/kg at 1 A/g in the voltage range of 0–1.4 V. These findings highlight the strong potential of this material as an electrode candidate for supercapacitor applications.
目前，现代世界需要发展更便宜、更高效的储能系统。因此，具有独特特性的超级电容器，包括电力输送、快速充电和延长循环寿命，已经吸引了很多人的兴趣。在这种情况下，十水草酸铈被认为是一种有趣的储能材料，因为它的结构优势可以提高比电容。在氧化还原添加剂电解质中对该材料进行了电化学研究，结果表明该材料具有电池式的电荷存储机制。在三电极配置中，该材料在1 a /g时的最大比电容为~ 1667 F/g。该非对称器件在0-1.4 V电压范围内，在1 a /g电压下提供了约552 F/g的比电容和令人印象深刻的约150 Wh/kg的能量密度。这些发现突出了这种材料作为超级电容器应用的电极候选材料的强大潜力。
{"title":"Redox additive mediated electrolyte for enhanced electrochemical performance of cerium oxalate based supercapacitors","authors":"Ann V. Lizbathu , Sajan Thomas , Neekha Deen Abraham , Jifi Jose , Bibily Baby , Ditty Dixon , P.R. Biju , Cyriac Joseph","doi":"10.1016/j.cap.2025.12.007","DOIUrl":"10.1016/j.cap.2025.12.007","url":null,"abstract":"<div><div>The evolution of energy storage systems that are less expensive and can perform efficiently is presently required for the modern world. Therefore, supercapacitors that possess unique characteristics including power delivery, fast recharging, and extended cycle life have been attracting lot of interest. In this vein, cerium oxalate decahydrate is considered to be an intriguing material for energy storage due to its structural benefits that can enhance specific capacitance. Electrochemical studies of the material were investigated in redox additive electrolyte, which revealed that the material possesses a battery-type charge storage mechanism. In three-electrode configuration, the material attained a maximum specific capacitance of ∼1667 F/g at 1 A/g. The asymmetric device delivered a specific capacitance of ∼552 F/g and an impressive energy density of ∼150 Wh/kg at 1 A/g in the voltage range of 0–1.4 V. These findings highlight the strong potential of this material as an electrode candidate for supercapacitor applications.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 128-139"},"PeriodicalIF":3.1,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797714","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 : 2025-12-13DOI: 10.1016/j.cap.2025.12.006
Hong-Hee Jeon, So-Won Kim, Jae-Hyuk Choi, Jun-Seo Hwang, Hee-Chul Lee
Precise and efficient plasma etching processes are key in fabricating next-generation semiconductor memory devices. However, further research is warranted on the selective etching of TiN and W electrode materials over the Hf0.5Zr0.5O2 (HZO) layer, particularly regarding the patterning of metal–ferroelectric–metal (MFM) device structures. This study aimed to improve the etch selectivity between TiN or W electrodes over HZO ferroelectric thin films for next-generation semiconductor memory device fabrication. To this end, we systematically analyzed dry etching characteristics by using Ar/CF4/O2/H2-based plasma. Specifically, we optimized process parameters, such as the RF power, process pressure, CF4/(Ar + CF4) gas mixing ratio, and addition ratios of O2 or H2, to achieve high etch selectivity between the TiN or W electrode films and HZO films. Under optimized conditions (an Ar:CF4 ratio of 7:3, RF power of 75 W, and process pressure of 120 mTorr), the etch selectivity for TiN/HZO and W/HZO reached maximum values of 142 and 332, respectively, demonstrating excellent performance. Furthermore, the addition of O2 enabled control over the etch rates of the TiN and W films and their selectivity over HZO films. Langmuir probe analysis and optical emission spectroscopy confirmed the enhancement in the chemical etching of the TiN and W electrodes due to the generation of F radicals. X-ray photoelectron spectroscopy analysis revealed the formation of fluorides on the etched film surfaces and an increase in the number of surface defects. The findings of this plasma etching study will potentially aid the advancement of fabrication technologies for ferroelectric memory devices.
{"title":"Plasma etching of TiN and W electrodes with high etch selectivity over HZO thin films","authors":"Hong-Hee Jeon, So-Won Kim, Jae-Hyuk Choi, Jun-Seo Hwang, Hee-Chul Lee","doi":"10.1016/j.cap.2025.12.006","DOIUrl":"10.1016/j.cap.2025.12.006","url":null,"abstract":"<div><div>Precise and efficient plasma etching processes are key in fabricating next-generation semiconductor memory devices. However, further research is warranted on the selective etching of TiN and W electrode materials over the Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> (HZO) layer, particularly regarding the patterning of metal–ferroelectric–metal (MFM) device structures. This study aimed to improve the etch selectivity between TiN or W electrodes over HZO ferroelectric thin films for next-generation semiconductor memory device fabrication. To this end, we systematically analyzed dry etching characteristics by using Ar/CF<sub>4</sub>/O<sub>2</sub>/H<sub>2</sub>-based plasma. Specifically, we optimized process parameters, such as the RF power, process pressure, CF<sub>4</sub>/(Ar + CF<sub>4</sub>) gas mixing ratio, and addition ratios of O<sub>2</sub> or H<sub>2</sub>, to achieve high etch selectivity between the TiN or W electrode films and HZO films. Under optimized conditions (an Ar:CF<sub>4</sub> ratio of 7:3, RF power of 75 W, and process pressure of 120 mTorr), the etch selectivity for TiN/HZO and W/HZO reached maximum values of 142 and 332, respectively, demonstrating excellent performance. Furthermore, the addition of O<sub>2</sub> enabled control over the etch rates of the TiN and W films and their selectivity over HZO films. Langmuir probe analysis and optical emission spectroscopy confirmed the enhancement in the chemical etching of the TiN and W electrodes due to the generation of F radicals. X-ray photoelectron spectroscopy analysis revealed the formation of fluorides on the etched film surfaces and an increase in the number of surface defects. The findings of this plasma etching study will potentially aid the advancement of fabrication technologies for ferroelectric memory devices.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 107-114"},"PeriodicalIF":3.1,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797715","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 : 2025-12-11DOI: 10.1016/j.cap.2025.12.005
Kyeong Jun Lee , Sihun Seong , Minji Park , Je-Ho Lee , Byeong-Gwan Cho , Tae Yeong Koo , Sang-Youn Park , Young Jun Chang , Maeng-Je Seong , Soonyong Park , Seo Hyoung Chang
Two tungsten-based transition metal dichalcogenides (TMDs), tungsten diselenide (WSe2) and ditelluride (WTe2), offer suitable model systems for investigating the interplay between crystal structures and 5d-orbital hybridization in layered transition-metal systems. Using W L3-edge x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS), we directly investigate the W 5d electronic states in polycrystalline TMDs samples. Combined with structural analyses, the white-line peaks in the XAS spectra, examined by their first-derivative peak positions, indicate symmetry-driven orbital states of WSe2 and WTe2. The corresponding RIXS spectra exhibit clearly distinct dd-excitations, indicating differences in W 5d orbital occupancy and ligand hybridization between the two compounds. This study provides a spectroscopic framework for understanding electronic structures of tungsten dichalcogenides in relation to chalcogen coordination changes and their topological and catalytic properties.
{"title":"W L3-edge x-ray study of 5d orbital excitations in WSe2 and WTe2","authors":"Kyeong Jun Lee , Sihun Seong , Minji Park , Je-Ho Lee , Byeong-Gwan Cho , Tae Yeong Koo , Sang-Youn Park , Young Jun Chang , Maeng-Je Seong , Soonyong Park , Seo Hyoung Chang","doi":"10.1016/j.cap.2025.12.005","DOIUrl":"10.1016/j.cap.2025.12.005","url":null,"abstract":"<div><div>Two tungsten-based transition metal dichalcogenides (TMDs), tungsten diselenide (WSe<sub>2</sub>) and ditelluride (WTe<sub>2</sub>), offer suitable model systems for investigating the interplay between crystal structures and 5<em>d</em>-orbital hybridization in layered transition-metal systems. Using W <em>L</em><sub>3</sub>-edge x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS), we directly investigate the W 5d electronic states in polycrystalline TMDs samples. Combined with structural analyses, the white-line peaks in the XAS spectra, examined by their first-derivative peak positions, indicate symmetry-driven orbital states of WSe<sub>2</sub> and WTe<sub>2</sub>. The corresponding RIXS spectra exhibit clearly distinct dd-excitations, indicating differences in W 5<em>d</em> orbital occupancy and ligand hybridization between the two compounds. This study provides a spectroscopic framework for understanding electronic structures of tungsten dichalcogenides in relation to chalcogen coordination changes and their topological and catalytic properties.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 102-106"},"PeriodicalIF":3.1,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797716","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 : 2025-12-11DOI: 10.1016/j.cap.2025.12.004
Mohammed Zamar Pasha , Faheem Ahmed Khan , N.M. Sudheep , C.J. Binish , G. Harisha , M.V. Murugendrappa , KS Krishna Kumar , Jobish Johns
This study explores the structural, mechanical, and dielectric properties of natural rubber (NR) blended with Caryota urens fruit extract (CUFE), with and without glutaraldehyde (GA) crosslinking, for sustainable dielectric materials. CUFE, rich in hydroxyl groups, was incorporated at varying concentrations to improve interfacial polarization and dielectric response. FTIR confirmed successful blending and crosslinking, while SEM revealed enhanced homogeneity with CUFE and GA treatment. Mechanical tests showed improved tensile strength and elongation at break, with optimum performance at 10 wt% CUFE. GA crosslinking enhanced dimensional stability but reduced elasticity due to network formation. Dielectric analysis indicated higher capacitance and lower impedance with increasing CUFE, driven by ionic and interfacial polarization. GA-crosslinked blends exhibited superior dielectric efficiency, with lower energy loss and higher charge storage capability. With flexibility, tunable conductivity, and strong dielectric performance, NR/CUFE blends show promise for flexible capacitors, wearable electronics, sensors, and sustainable devices.
{"title":"Flexible and sustainable dielectric materials from natural rubber and Caryota urens extract for wearable and soft electronic devices","authors":"Mohammed Zamar Pasha , Faheem Ahmed Khan , N.M. Sudheep , C.J. Binish , G. Harisha , M.V. Murugendrappa , KS Krishna Kumar , Jobish Johns","doi":"10.1016/j.cap.2025.12.004","DOIUrl":"10.1016/j.cap.2025.12.004","url":null,"abstract":"<div><div>This study explores the structural, mechanical, and dielectric properties of natural rubber (NR) blended with <em>Caryota urens</em> fruit extract (CUFE), with and without glutaraldehyde (GA) crosslinking, for sustainable dielectric materials. CUFE, rich in hydroxyl groups, was incorporated at varying concentrations to improve interfacial polarization and dielectric response. FTIR confirmed successful blending and crosslinking, while SEM revealed enhanced homogeneity with CUFE and GA treatment. Mechanical tests showed improved tensile strength and elongation at break, with optimum performance at 10 wt% CUFE. GA crosslinking enhanced dimensional stability but reduced elasticity due to network formation. Dielectric analysis indicated higher capacitance and lower impedance with increasing CUFE, driven by ionic and interfacial polarization. GA-crosslinked blends exhibited superior dielectric efficiency, with lower energy loss and higher charge storage capability. With flexibility, tunable conductivity, and strong dielectric performance, NR/CUFE blends show promise for flexible capacitors, wearable electronics, sensors, and sustainable devices.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 65-78"},"PeriodicalIF":3.1,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748660","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 : 2025-12-11DOI: 10.1016/j.cap.2025.11.016
Chettiagounder Sengodan Boopathi , Karnam Chandrakumar Ramya , Youssef Trabelsi , K. Sudha , Taha Sheheryar
The demand for efficient solar energy harvesting has driven the development of absorbers capable of operating across wide frequency bands while maintaining stability under practical conditions. Traditional absorber designs usually face challenges such as narrowband operation, polarization sensitivity, poor angular stability and reliance on complex fabrication routes, which limit their applicability in large-scale solar thermal and thermophotovoltaic systems. To address these constraints, a nickel-polyimide-nickel metasurface absorber is proposed in a metal-dielectric-metal architecture. The nested concentric resonator design promotes strong plasmonic coupling and broadband impedance matching that enables absorption above 90 % across 129.64–3621.5 THz (wavelengths 82.8–2314.0 nm) with an average of 94.58 % while maintaining over 80 % absorption beyond 4000 THz. The absorber achieves 93.59 % solar absorption efficiency under the AM 1.5 spectrum, exhibits thermal emission efficiency of 93.35 % at 3500 K and reaches solar-to-electrical conversion efficiencies up to 64.61 % under high solar concentration. In addition, it shows polarization independence and stable performance up to 50° incidence angle. By uniting ultra-broadband response and thermal resilience, the design establishes a pathway toward multifunctional absorbers for next-generation solar energy harvesting and photothermal conversion technologies.
{"title":"Ultra-wideband and angular-stable terahertz absorber with thermal stability for solar–thermal applications","authors":"Chettiagounder Sengodan Boopathi , Karnam Chandrakumar Ramya , Youssef Trabelsi , K. Sudha , Taha Sheheryar","doi":"10.1016/j.cap.2025.11.016","DOIUrl":"10.1016/j.cap.2025.11.016","url":null,"abstract":"<div><div>The demand for efficient solar energy harvesting has driven the development of absorbers capable of operating across wide frequency bands while maintaining stability under practical conditions. Traditional absorber designs usually face challenges such as narrowband operation, polarization sensitivity, poor angular stability and reliance on complex fabrication routes, which limit their applicability in large-scale solar thermal and thermophotovoltaic systems. To address these constraints, a nickel-polyimide-nickel metasurface absorber is proposed in a metal-dielectric-metal architecture. The nested concentric resonator design promotes strong plasmonic coupling and broadband impedance matching that enables absorption above 90 % across 129.64–3621.5 THz (wavelengths 82.8–2314.0 nm) with an average of 94.58 % while maintaining over 80 % absorption beyond 4000 THz. The absorber achieves 93.59 % solar absorption efficiency under the AM 1.5 spectrum, exhibits thermal emission efficiency of 93.35 % at 3500 K and reaches solar-to-electrical conversion efficiencies up to 64.61 % under high solar concentration. In addition, it shows polarization independence and stable performance up to 50° incidence angle. By uniting ultra-broadband response and thermal resilience, the design establishes a pathway toward multifunctional absorbers for next-generation solar energy harvesting and photothermal conversion technologies.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 90-101"},"PeriodicalIF":3.1,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748662","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 : 2025-12-06DOI: 10.1016/j.cap.2025.11.017
Hyerin Kim , Jieun Yoo , Yeongseo Kim , Hyunsoo Kim , Yerin Go , Dahyun Yum , Taeyoung Choi
We present a fluorescence-based method for optimizing electro-optic modulator (EOM) performance using a single trapped ion. By comparing fluorescence from a trapped ion with optical cavity measurements, we determine modulation conditions for optimizing optical sidebands, which is essential for driving various transitions relevant to ion-qubit manipulation. We also observe enhanced fluorescence from a trapped ion when applying high-power pulsed laser without EOM modulation. Since the pulsed laser is used for performing quantum gates on individual ions, this fluorescence signal can serve as a diagnostic tool for aligning the ion with a tightly focused laser beam. These results provide a practical method for optimizing sideband generation and diagnosing spatial beam overlap in trapped-ion quantum systems.
{"title":"Single-ion fluorescence probing of electro-optic modulator efficiency and Raman coupling in trapped-ion system","authors":"Hyerin Kim , Jieun Yoo , Yeongseo Kim , Hyunsoo Kim , Yerin Go , Dahyun Yum , Taeyoung Choi","doi":"10.1016/j.cap.2025.11.017","DOIUrl":"10.1016/j.cap.2025.11.017","url":null,"abstract":"<div><div>We present a fluorescence-based method for optimizing electro-optic modulator (EOM) performance using a single trapped ion. By comparing fluorescence from a trapped ion with optical cavity measurements, we determine modulation conditions for optimizing optical sidebands, which is essential for driving various transitions relevant to ion-qubit manipulation. We also observe enhanced fluorescence from a trapped ion when applying high-power pulsed laser without EOM modulation. Since the pulsed laser is used for performing quantum gates on individual ions, this fluorescence signal can serve as a diagnostic tool for aligning the ion with a tightly focused laser beam. These results provide a practical method for optimizing sideband generation and diagnosing spatial beam overlap in trapped-ion quantum systems.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 53-58"},"PeriodicalIF":3.1,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748659","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 : 2025-12-05DOI: 10.1016/j.cap.2025.12.003
Minhyuk Choi , Resta Agung Susilo , Hyeongwoo Seo , Jiafeng Yan , Pyosang Kim , Hyeonsu Kim , Jaeyong Kim , Donghoon Seoung , Jun Sung Kim
To investigate the pressure effect on exchange interactions and the magnetic phase of YMn6Sn6, we performed X-ray diffraction and electrical transport measurements at the high pressure up to 18 GPa using diamond anvil cell. Both experimental results confirmed no structural transition, while low-temperature magnetoresistance measurements revealed that the forced-ferromagnetic transition field is significantly suppressed with increasing pressure. These results can be understood as a pressure-induced reduction of the antiferromagnetic exchange interaction, demonstrating that lattice compression under pressure effectively modifies the magnetic ground state of the 166-type Kagome magnet.
{"title":"Pressure-tuning of magnetic transition in a kagome antiferromagnet, YMn6Sn6","authors":"Minhyuk Choi , Resta Agung Susilo , Hyeongwoo Seo , Jiafeng Yan , Pyosang Kim , Hyeonsu Kim , Jaeyong Kim , Donghoon Seoung , Jun Sung Kim","doi":"10.1016/j.cap.2025.12.003","DOIUrl":"10.1016/j.cap.2025.12.003","url":null,"abstract":"<div><div>To investigate the pressure effect on exchange interactions and the magnetic phase of YMn<sub>6</sub>Sn<sub>6</sub>, we performed X-ray diffraction and electrical transport measurements at the high pressure up to <span><math><mo>∼</mo></math></span> 18 GPa using diamond anvil cell. Both experimental results confirmed no structural transition, while low-temperature magnetoresistance measurements revealed that the forced-ferromagnetic transition field is significantly suppressed with increasing pressure. These results can be understood as a pressure-induced reduction of the antiferromagnetic exchange interaction, demonstrating that lattice compression under pressure effectively modifies the magnetic ground state of the 166-type Kagome magnet.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 115-119"},"PeriodicalIF":3.1,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797717","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 : 2025-12-03DOI: 10.1016/j.cap.2025.12.001
Haeyoon Jung , Indukuru Ramesh Reddy , Bongjae Kim , Jiyeon Kim , Sooran Kim
LaMn7O12, a quadruple perovskite oxide (AA'3B4O12-type), has attracted attention for its notable bifunctional activity in oxygen evolution and reduction reactions. Here, we systematically investigate the magnetic phase diagram and lattice dynamics of LaMn7O12 using two density functional theory plus Hubbard U (DFT + U) approaches: the spin-density and the charge-only-density formalism. Phase diagram analysis as a function of U and J shows that both methods stabilize the experimentally observed antiferromagnetic (AFM) configuration (C-type AFM at the B-site and ferrimagnetic structure at the A′-site Mn ions) at U = 3.5 eV and J = 0.8 eV. These U and J values are consistent with those obtained from the constrained random phase approximation. Furthermore, we observe the dynamical stability of the AFM phase through phonon dispersion curves and analyze the Raman-active phonon modes. These results highlight the critical role of appropriate U and J parameters in accurately describing the properties of LaMn7O12.
{"title":"Correlation effects on magnetic structure and lattice dynamics of LaMn7O12: A first-principles study","authors":"Haeyoon Jung , Indukuru Ramesh Reddy , Bongjae Kim , Jiyeon Kim , Sooran Kim","doi":"10.1016/j.cap.2025.12.001","DOIUrl":"10.1016/j.cap.2025.12.001","url":null,"abstract":"<div><div>LaMn<sub>7</sub>O<sub>12</sub>, a quadruple perovskite oxide (AA'<sub>3</sub>B<sub>4</sub>O<sub>12</sub>-type), has attracted attention for its notable bifunctional activity in oxygen evolution and reduction reactions. Here, we systematically investigate the magnetic phase diagram and lattice dynamics of LaMn<sub>7</sub>O<sub>12</sub> using two density functional theory plus Hubbard <em>U</em> (DFT + <em>U</em>) approaches: the spin-density and the charge-only-density formalism. Phase diagram analysis as a function of <em>U</em> and <em>J</em> shows that both methods stabilize the experimentally observed antiferromagnetic (AFM) configuration (C-type AFM at the B-site and ferrimagnetic structure at the A′-site Mn ions) at <em>U</em> = 3.5 eV and <em>J</em> = 0.8 eV. These <em>U</em> and <em>J</em> values are consistent with those obtained from the constrained random phase approximation. Furthermore, we observe the dynamical stability of the AFM phase through phonon dispersion curves and analyze the Raman-active phonon modes. These results highlight the critical role of appropriate <em>U</em> and <em>J</em> parameters in accurately describing the properties of LaMn<sub>7</sub>O<sub>12</sub>.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 59-64"},"PeriodicalIF":3.1,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748661","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 : 2025-12-02DOI: 10.1016/j.cap.2025.12.002
Hue Tran , Yugyeong Je , Hyunjeong Jeong , Eleanor E.B. Campbell , Ki Kang Kim , Sang Wook Lee
The energy barrier height of ZnO microwire electrical contacts is tuned by inducing piezoelectric polarization charges at the local metal-semiconductor interface when a mechanical deformation is applied to the ZnO microwire. Strain is introduced in the individual ZnO microwire by compressive stress applied along the axial direction, which controllably bends the microwire, observed in an optical microscope. As a result, the metal-semiconductor local contact can transform from Schottky to Ohmic and vice versa. This work demonstrates a simple method for controlling the electrical properties of ZnO nanowires to achieve reversible tuning between Schottky and Ohmic contact on one device by combining in-situ measurement with mechanical manipulation. This can contribute to the development of multifunctional and Ohmic/Schottky-based sensors, switches, rectifiers, and other functional electronic devices.
{"title":"Reversible conversion between Schottky and ohmic contacts of zinc oxide microwire under piezoelectric potential manipulation","authors":"Hue Tran , Yugyeong Je , Hyunjeong Jeong , Eleanor E.B. Campbell , Ki Kang Kim , Sang Wook Lee","doi":"10.1016/j.cap.2025.12.002","DOIUrl":"10.1016/j.cap.2025.12.002","url":null,"abstract":"<div><div>The energy barrier height of ZnO microwire electrical contacts is tuned by inducing piezoelectric polarization charges at the local metal-semiconductor interface when a mechanical deformation is applied to the ZnO microwire. Strain is introduced in the individual ZnO microwire by compressive stress applied along the axial direction, which controllably bends the microwire, observed in an optical microscope. As a result, the metal-semiconductor local contact can transform from Schottky to Ohmic and <em>vice versa</em>. This work demonstrates a simple method for controlling the electrical properties of ZnO nanowires to achieve reversible tuning between Schottky and Ohmic contact on one device by combining <em>in-situ</em> measurement with mechanical manipulation. This can contribute to the development of multifunctional and Ohmic/Schottky-based sensors, switches, rectifiers, and other functional electronic devices.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 22-27"},"PeriodicalIF":3.1,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692528","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 the solution-processing method of perovskites, selecting appropriate solvents for each precursor is crucial for synthesizing homogeneous perovskite films, as the interaction energy and mechanism between each solvent and precursor vary significantly. In this study, we used dimethylacetamide (DMAc) as the host solvent instead of dimethylformamide to match the Hansen solubility parameters (HSP) with N-methyl-2-pyrrolidone (NMP) and anti-solvent. DMAc-based perovskite facilitates the formation of intermediate phase with NMP due to well-matched HSP, resulting in formation of a glossy perovskite film. However, the power conversion efficiency (PCE) of DMAc-based perovskite solar cells did not improve, primarily because of the formation of small grains. Although methylammonium chloride (MACl) was introduced as an additive to promote grain growth, no significant enhancement in the PCE was observed, likely due to the low interaction energy between MACl and NMP. These findings enhance our understanding of solvent-precursor interactions by applying HSP theory and MACl additive.
{"title":"Solvent–precursor interaction engineering for formamidinium-based perovskites: Role of dimethylacetamide, N-methyl-2-pyrrolidone, and methylammonium chloride in film formation and device performance","authors":"Muntae Hwang, Il-Wook Cho, Hyunbok Lee, Mee-Yi Ryu","doi":"10.1016/j.cap.2025.11.010","DOIUrl":"10.1016/j.cap.2025.11.010","url":null,"abstract":"<div><div>In the solution-processing method of perovskites, selecting appropriate solvents for each precursor is crucial for synthesizing homogeneous perovskite films, as the interaction energy and mechanism between each solvent and precursor vary significantly. In this study, we used dimethylacetamide (DMAc) as the host solvent instead of dimethylformamide to match the Hansen solubility parameters (HSP) with N-methyl-2-pyrrolidone (NMP) and anti-solvent. DMAc-based perovskite facilitates the formation of intermediate phase with NMP due to well-matched HSP, resulting in formation of a glossy perovskite film. However, the power conversion efficiency (PCE) of DMAc-based perovskite solar cells did not improve, primarily because of the formation of small grains. Although methylammonium chloride (MACl) was introduced as an additive to promote grain growth, no significant enhancement in the PCE was observed, likely due to the low interaction energy between MACl and NMP. These findings enhance our understanding of solvent-precursor interactions by applying HSP theory and MACl additive.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"83 ","pages":"Pages 15-21"},"PeriodicalIF":3.1,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692525","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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