Pub Date : 2025-12-18DOI: 10.1016/j.physb.2025.418205
Badr Akharkhach, Abdelfettah Barhdadi
Iron doped TiO2 is a highly efficient photo-catalytic material that has also an extended response to visible light. Herein we apply DFT method to thoroughly investigate the effect iron doping on the electronic structure and optical properties of the TiO2 (1 1 0) rutile surface, as well as the oxidation states taken by iron at each doping site. Our calculations predict that iron will adopt the lowest possible oxidation state (+2) when it occupies an interstitial site. At a sixfold coordinated doping site, the nearness from the bridging oxygen vacancy dictates the iron's oxidation state which ranges from +2 to +4. Iron will have the same oxidation state (+4) when it occupies a fivefold or a sixfold doping site though this is just a metastable state. Furthermore, if a nearby oxygen vacancy occurs, the iron's oxidation state in both of these sites will decrease to the same value (+3).
{"title":"Study of the iron doped TiO2 surface as a promising self-cleaning material: first principles insights","authors":"Badr Akharkhach, Abdelfettah Barhdadi","doi":"10.1016/j.physb.2025.418205","DOIUrl":"10.1016/j.physb.2025.418205","url":null,"abstract":"<div><div>Iron doped TiO<sub>2</sub> is a highly efficient photo-catalytic material that has also an extended response to visible light. Herein we apply DFT method to thoroughly investigate the effect iron doping on the electronic structure and optical properties of the TiO<sub>2</sub> (1 1 0) rutile surface, as well as the oxidation states taken by iron at each doping site. Our calculations predict that iron will adopt the lowest possible oxidation state (+2) when it occupies an interstitial site. At a sixfold coordinated doping site, the nearness from the bridging oxygen vacancy dictates the iron's oxidation state which ranges from +2 to +4. Iron will have the same oxidation state (+4) when it occupies a fivefold or a sixfold doping site though this is just a metastable state. Furthermore, if a nearby oxygen vacancy occurs, the iron's oxidation state in both of these sites will decrease to the same value (+3).</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418205"},"PeriodicalIF":2.8,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2025-12-17DOI: 10.1016/j.physb.2025.418201
Dong Thi Kim Phuong , Nguyen Quoc Khanh , Dang Khanh Linh , Nguyen Van Men
We investigate plasmon properties in a spin-polarized monolayer graphene system under the influence of an in-plane external magnetic field at finite temperature. The results show that the plasmon mode persists inside the single-particle excitation region, although it becomes weakly damped at small wave vectors. In contrast to unpolarized system, where the plasmon frequency exhibits a strong and non-monotonic temperature dependence, we find that spin polarization substantially suppresses this temperature sensitivity: the relative change of the plasmon frequency with temperature is much weaker in the spin-polarized case, and the weakly damped plasmon regime extends to higher temperatures. At low temperatures, the plasmon frequency (damping rate) increases (decreases) with temperature, whereas at higher temperatures, the opposite trend is observed. In addition, both the plasmon frequency and damping rate increase notably with spin polarization. These findings provide valuable insight into the interplay between temperature and spin polarization for collective excitations in graphene.
{"title":"Temperature-dependent plasmon excitations in spin-polarized monolayer graphene","authors":"Dong Thi Kim Phuong , Nguyen Quoc Khanh , Dang Khanh Linh , Nguyen Van Men","doi":"10.1016/j.physb.2025.418201","DOIUrl":"10.1016/j.physb.2025.418201","url":null,"abstract":"<div><div>We investigate plasmon properties in a spin-polarized monolayer graphene system under the influence of an in-plane external magnetic field at finite temperature. The results show that the plasmon mode persists inside the single-particle excitation region, although it becomes weakly damped at small wave vectors. In contrast to unpolarized system, where the plasmon frequency exhibits a strong and non-monotonic temperature dependence, we find that spin polarization substantially suppresses this temperature sensitivity: the relative change of the plasmon frequency with temperature is much weaker in the spin-polarized case, and the weakly damped plasmon regime extends to higher temperatures. At low temperatures, the plasmon frequency (damping rate) increases (decreases) with temperature, whereas at higher temperatures, the opposite trend is observed. In addition, both the plasmon frequency and damping rate increase notably with spin polarization. These findings provide valuable insight into the interplay between temperature and spin polarization for collective excitations in graphene.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418201"},"PeriodicalIF":2.8,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
We investigate Coulomb screening and plasmon excitations in Y-shaped Kekulé-patterned graphene within the random phase approximation and using a tight-binding model that incorporates both hopping strength and on-site energy deviations. The Kekulé distortion alters the low-energy bands, lifting valley degeneracy, and introducing particle-hole asymmetry. These modifications are reflected in the static polarizability, exhibiting a strong dependence on the chemical potential. In particular, it shows a pronounced and tunable Kohn anomaly compared to pristine graphene. Plasmon excitations are strongly influenced by structural distortions and chemical potential variations, yet they preserve the square-root dependence of two-dimensional electron gas (2DEG) spectra in the long-wavelength limit, albeit with a modified chemical potential response. Notably, the plasmon modes exhibit a hybrid character, merging features of both pristine and gapped graphene, thereby reflecting the presence of linear and gapped dispersion within the system. This tunability enables controlled modulation of plasmon, highlighting potential applications in plasmonic devices.
{"title":"Coulomb screening and collective excitations in Y-shaped Kekulé-patterned graphene","authors":"Haniye Alimohammadi , Borhan Arghavani Nia , Yawar Mohammadi , Sahar Rezaee","doi":"10.1016/j.physb.2025.418202","DOIUrl":"10.1016/j.physb.2025.418202","url":null,"abstract":"<div><div>We investigate Coulomb screening and plasmon excitations in Y-shaped Kekulé-patterned graphene within the random phase approximation and using a tight-binding model that incorporates both hopping strength and on-site energy deviations. The Kekulé distortion alters the low-energy bands, lifting valley degeneracy, and introducing particle-hole asymmetry. These modifications are reflected in the static polarizability, exhibiting a strong dependence on the chemical potential. In particular, it shows a pronounced and tunable Kohn anomaly compared to pristine graphene. Plasmon excitations are strongly influenced by structural distortions and chemical potential variations, yet they preserve the square-root dependence of two-dimensional electron gas (2DEG) spectra in the long-wavelength limit, albeit with a modified chemical potential response. Notably, the plasmon modes exhibit a hybrid character, merging features of both pristine and gapped graphene, thereby reflecting the presence of linear and gapped dispersion within the system. This tunability enables controlled modulation of plasmon, highlighting potential applications in plasmonic devices.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418202"},"PeriodicalIF":2.8,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2025-12-17DOI: 10.1016/j.physb.2025.418187
Ghada El Fidha , Nabila Bitri , Eduard Llobet
Ni–Co co-doped ZnO thin films were synthesized on glass substrates via the spray pyrolysis technique to investigate the synergistic effect of dual doping on photocatalytic performance. The incorporation of Ni and Co ions effectively modified the structural, morphological, and optical properties of ZnO, as confirmed by XRD, SEM, AFM, EDX, and UV–vis spectroscopy. Photocatalytic tests under sunlight irradiation showed a remarkable enhancement in methylene blue degradation for Ni–Co co-doped ZnO films. In particular, 1.5 % Ni–Co co-doped ZnO achieves a 95 % degradation efficiency after 180 min of sunlight exposure.
{"title":"Boosting photocatalytic efficiency through Ni–Co co-doped ZnO thin films fabricated by spray pyrolysis","authors":"Ghada El Fidha , Nabila Bitri , Eduard Llobet","doi":"10.1016/j.physb.2025.418187","DOIUrl":"10.1016/j.physb.2025.418187","url":null,"abstract":"<div><div>Ni–Co co-doped ZnO thin films were synthesized on glass substrates via the spray pyrolysis technique to investigate the synergistic effect of dual doping on photocatalytic performance. The incorporation of Ni and Co ions effectively modified the structural, morphological, and optical properties of ZnO, as confirmed by XRD, SEM, AFM, EDX, and UV–vis spectroscopy. Photocatalytic tests under sunlight irradiation showed a remarkable enhancement in methylene blue degradation for Ni–Co co-doped ZnO films. In particular, 1.5 % Ni–Co co-doped ZnO achieves a 95 % degradation efficiency after 180 min of sunlight exposure.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418187"},"PeriodicalIF":2.8,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2025-12-16DOI: 10.1016/j.physb.2025.418184
Lina Si, Hong Li, Fengbin Liu
Two-dimensional metal–semiconductor heterostructures are pivotal for the development of next-generation electronics. We conduct a comprehensive first-principles investigation on contact properties between Janus MoSH and SiC monolayers. Both the MoHS/SiC and MoSH/SiC heterostructures exhibit robust stability. The MoHS/SiC interface is governed by weak van der Waals interactions, effectively preserving the intrinsic band structures of the individual layers, whereas the MoSH/SiC system features significantly stronger interfacial coupling, leading to pronounced modifications in band dispersion and charge redistribution across the interface. The MoHS/SiC heterojunction establishes a p-type quasi-Ohmic contact, while the MoSH/SiC counterpart exhibits an n-type Schottky contact. Crucially, the MoHS/SiC system undergoes a transition from quasi-Ohmic to full p-type Ohmic contact under an external electric field exceeding 0.2 V/Å. Our results offer essential insights into the rational design of high-efficiency 2D electronic systems.
{"title":"Interfacial engineering between Janus MoSH and SiC monolayers: A first-principles study","authors":"Lina Si, Hong Li, Fengbin Liu","doi":"10.1016/j.physb.2025.418184","DOIUrl":"10.1016/j.physb.2025.418184","url":null,"abstract":"<div><div>Two-dimensional metal–semiconductor heterostructures are pivotal for the development of next-generation electronics. We conduct a comprehensive first-principles investigation on contact properties between Janus MoSH and SiC monolayers. Both the MoHS/SiC and MoSH/SiC heterostructures exhibit robust stability. The MoHS/SiC interface is governed by weak van der Waals interactions, effectively preserving the intrinsic band structures of the individual layers, whereas the MoSH/SiC system features significantly stronger interfacial coupling, leading to pronounced modifications in band dispersion and charge redistribution across the interface. The MoHS/SiC heterojunction establishes a <em>p</em>-type quasi-Ohmic contact, while the MoSH/SiC counterpart exhibits an <em>n</em>-type Schottky contact. Crucially, the MoHS/SiC system undergoes a transition from quasi-Ohmic to full <em>p</em>-type Ohmic contact under an external electric field exceeding 0.2 V/Å. Our results offer essential insights into the rational design of high-efficiency 2D electronic systems.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418184"},"PeriodicalIF":2.8,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2025-12-16DOI: 10.1016/j.physb.2025.418186
M.S. Gaafar
Tellurite-tungstate glasses are widely recognized for their unique interactions with radiation and light. However, the impact of replacing a rare-earth oxide for a fluoride modifier on the structure and functioning of these glasses has yet to be fully studied. The substitution of Sm2O3 for NaF in a 65TeO2-15WO3-10MnO glass system has not been completely researched, and the related structure-property-function links have not been characterized. A series of 65TeO2-15WO3-10MnO-(9−x)NaF-xSm2O3 (x = 1.0–3.0 mol%) glasses were produced using the melt-quenching method to study their structural evolution and variations in thermal, mechanical, and radiation-shielding characteristics. The role of Sm2O3 substitution was investigated using a comprehensive multi-technique approach that included Raman spectroscopy, FTIR analysis, X-ray radical distribution function (RDF), differential scanning calorimetry (DSC), ultrasonic measurements, density–molar volume analysis, elastic moduli, and radiation shielding simulations. As the Sm2O3 concentration increases, structural investigations confirm a progressive conversion of TeO4 to TeO3 and WO6 to WO4 units, as well as the formation of Sm–O and Te–O–Sm links and an increase in non-bridging oxygen species. This structural alteration significantly alters the connection and stiffness of the glass network. Thermal findings indicate an improvement in both the stable supercooled liquid area and the glass transition temperature. According to a mechanical study, stronger Sm–O bonds have formed, improving the elastic moduli as well. This improvement is consistent with theoretical predictions. Furthermore, the inclusion of heavy Sm3+ ions increases the mass attenuation coefficient and effective atomic number, enabling the glasses to block γ-rays more effectively than ordinary concrete and commercial RS-type glasses. For the first time, the combined structural tuning, enhanced thermal stability, mechanical reinforcement, and superior radiation-shielding effectiveness demonstrate the multifunctionality of SmO3-modified tellurite–tungstate glasses. This indicates that they might be very beneficial for radiation protection and cutting-edge technologies.
{"title":"Impact of Sm2O3 substitution on the structure and multifunctional properties of tellurite–tungstate glasses","authors":"M.S. Gaafar","doi":"10.1016/j.physb.2025.418186","DOIUrl":"10.1016/j.physb.2025.418186","url":null,"abstract":"<div><div>Tellurite-tungstate glasses are widely recognized for their unique interactions with radiation and light. However, the impact of replacing a rare-earth oxide for a fluoride modifier on the structure and functioning of these glasses has yet to be fully studied. The substitution of Sm<sub>2</sub>O<sub>3</sub> for NaF in a 65TeO<sub>2</sub>-15WO<sub>3</sub>-10MnO glass system has not been completely researched, and the related structure-property-function links have not been characterized. A series of 65TeO<sub>2</sub>-15WO<sub>3</sub>-10MnO-(9−x)NaF-xSm<sub>2</sub>O<sub>3</sub> (x = 1.0–3.0 mol%) glasses were produced using the melt-quenching method to study their structural evolution and variations in thermal, mechanical, and radiation-shielding characteristics. The role of Sm<sub>2</sub>O<sub>3</sub> substitution was investigated using a comprehensive multi-technique approach that included Raman spectroscopy, FTIR analysis, X-ray radical distribution function (RDF), differential scanning calorimetry (DSC), ultrasonic measurements, density–molar volume analysis, elastic moduli, and radiation shielding simulations. As the Sm<sub>2</sub>O<sub>3</sub> concentration increases, structural investigations confirm a progressive conversion of TeO<sub>4</sub> to TeO<sub>3</sub> and WO<sub>6</sub> to WO<sub>4</sub> units, as well as the formation of Sm–O and Te–O–Sm links and an increase in non-bridging oxygen species. This structural alteration significantly alters the connection and stiffness of the glass network. Thermal findings indicate an improvement in both the stable supercooled liquid area and the glass transition temperature. According to a mechanical study, stronger Sm–O bonds have formed, improving the elastic moduli as well. This improvement is consistent with theoretical predictions. Furthermore, the inclusion of heavy Sm<sup>3+</sup> ions increases the mass attenuation coefficient and effective atomic number, enabling the glasses to block γ-rays more effectively than ordinary concrete and commercial RS-type glasses. For the first time, the combined structural tuning, enhanced thermal stability, mechanical reinforcement, and superior radiation-shielding effectiveness demonstrate the multifunctionality of SmO<sub>3</sub>-modified tellurite–tungstate glasses. This indicates that they might be very beneficial for radiation protection and cutting-edge technologies.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418186"},"PeriodicalIF":2.8,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2025-12-16DOI: 10.1016/j.physb.2025.418171
Ting Fu , Ming Wang , Xiaolei Yang , Ruofei Chen , Lei Zhao , Guchang Han , Yungui Ma
Due to the process fluctuations in the fabrication of magnetic storage devices and the competitive relationship among the write error rate, the endurance and power consumption, the effective write window of these devices is limited. In this work, we investigated various switching modes that occur in magnetic tunnel junctions with perpendicular magnetic anisotropy under conditions of high write voltage and low write error rate. The curve of the write error rate versus voltage shows multiple anomalous branches. Through simulations, it is found that the balloon and hump-type anomalies are more significantly related to the intermediate states caused by defects in the free layer. The local stress and pinning fields induced by these defects impede the magnetization switching process, and their intensities are independent of temperature. Additionally, experiments demonstrate that both the balloon and hump-type anomalous branches can be suppressed by applying a small vertical magnetic field. Reducing the device size and enhancing the perpendicular magnetic anisotropy of the free layer can mitigate the occurrence of the above anomalies. All these findings provide extensive solutions for improving the write margin of spin-transfer torque magnetic random access memory.
{"title":"The influence factors of write margin in a cell of perpendicular STT-MRAM","authors":"Ting Fu , Ming Wang , Xiaolei Yang , Ruofei Chen , Lei Zhao , Guchang Han , Yungui Ma","doi":"10.1016/j.physb.2025.418171","DOIUrl":"10.1016/j.physb.2025.418171","url":null,"abstract":"<div><div>Due to the process fluctuations in the fabrication of magnetic storage devices and the competitive relationship among the write error rate, the endurance and power consumption, the effective write window of these devices is limited. In this work, we investigated various switching modes that occur in magnetic tunnel junctions with perpendicular magnetic anisotropy under conditions of high write voltage and low write error rate. The curve of the write error rate versus voltage shows multiple anomalous branches. Through simulations, it is found that the balloon and hump-type anomalies are more significantly related to the intermediate states caused by defects in the free layer. The local stress and pinning fields induced by these defects impede the magnetization switching process, and their intensities are independent of temperature. Additionally, experiments demonstrate that both the balloon and hump-type anomalous branches can be suppressed by applying a small vertical magnetic field. Reducing the device size and enhancing the perpendicular magnetic anisotropy of the free layer can mitigate the occurrence of the above anomalies. All these findings provide extensive solutions for improving the write margin of spin-transfer torque magnetic random access memory.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418171"},"PeriodicalIF":2.8,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2025-12-15DOI: 10.1016/j.physb.2025.418173
Peng-wei Wang , Ming-fei Li , Yi-jie Wang , Chuan-Nan Ge , Cheng-Long Lei , Wei-Chong Choo
As high entropy alloys (HEAs) emerge as structural materials, clarifying their deformation mechanisms is essential. Using molecular dynamics (MD) simulations, this study compares tensile behavior of single-crystal and polycrystalline FeNiCrCuAl HEAs. Both exhibit stable atomic structures, and polycrystalline HEAs show broader and lower radial distribution function peaks due to grain boundary distortions. Although their elastic responses are similar, the single-crystal HEA achieves higher peak stress with sharp drops, whereas the polycrystalline model demonstrates lower strength but stable plasticity. Phase transformations occur in both, with HCP forming earlier in polycrystalline. Dislocation evolution also differs because the polycrystalline model has a higher initial dislocation density, while single crystals rapidly accumulate dislocations that lead to strain localization. Shear bands align with crystallographic orientations in single crystals but nucleate at grain boundaries in polycrystalline. These findings highlight the critical role of grain boundaries in governing HEA deformation and provide guidance for optimizing mechanical performance.
{"title":"A systematic comparison of single-crystal and polycrystalline models in predicting high-entropy alloys deformation behavior","authors":"Peng-wei Wang , Ming-fei Li , Yi-jie Wang , Chuan-Nan Ge , Cheng-Long Lei , Wei-Chong Choo","doi":"10.1016/j.physb.2025.418173","DOIUrl":"10.1016/j.physb.2025.418173","url":null,"abstract":"<div><div>As high entropy alloys (HEAs) emerge as structural materials, clarifying their deformation mechanisms is essential. Using molecular dynamics (MD) simulations, this study compares tensile behavior of single-crystal and polycrystalline FeNiCrCuAl HEAs. Both exhibit stable atomic structures, and polycrystalline HEAs show broader and lower radial distribution function peaks due to grain boundary distortions. Although their elastic responses are similar, the single-crystal HEA achieves higher peak stress with sharp drops, whereas the polycrystalline model demonstrates lower strength but stable plasticity. Phase transformations occur in both, with HCP forming earlier in polycrystalline. Dislocation evolution also differs because the polycrystalline model has a higher initial dislocation density, while single crystals rapidly accumulate dislocations that lead to strain localization. Shear bands align with crystallographic orientations in single crystals but nucleate at grain boundaries in polycrystalline. These findings highlight the critical role of grain boundaries in governing HEA deformation and provide guidance for optimizing mechanical performance.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418173"},"PeriodicalIF":2.8,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2025-12-15DOI: 10.1016/j.physb.2025.418181
Hongyi Cao , Fanhui Xie , Qingmiao Nie , Chaojun Tang , Bo Yan , Fanxin Liu , Zhendong Yan , Ping Gu , Zhong Huang
We studied the electrically tunable and ultra-narrowband high absorption in monolayer graphene near the optical communication wavelength of 1550 nm. The graphene was sandwiched between one-dimensional arrays of metal strips and a dielectric layer deposited on a metal substrate. The excitation of surface plasmon polaritons (SPPs) in metal substrate significantly enhanced the light absorption in graphene, while the extremely low radiative damping of SPPs resulted in an ultra-narrow absorption bandwidth of merely several nanometers. Furthermore, by applying an external electric bias to dynamically tune the Fermi energy of graphene, the ultra-narrowband absorption achieved a near-perfect modulation depth of 100 %. This work has potential applications for graphene-based electro-optic modulators in the optical communication system.
{"title":"Ultra-narrowband graphene light absorption enhancement with near-perfect modulation for 1550 nm optical communication","authors":"Hongyi Cao , Fanhui Xie , Qingmiao Nie , Chaojun Tang , Bo Yan , Fanxin Liu , Zhendong Yan , Ping Gu , Zhong Huang","doi":"10.1016/j.physb.2025.418181","DOIUrl":"10.1016/j.physb.2025.418181","url":null,"abstract":"<div><div>We studied the electrically tunable and ultra-narrowband high absorption in monolayer graphene near the optical communication wavelength of 1550 nm. The graphene was sandwiched between one-dimensional arrays of metal strips and a dielectric layer deposited on a metal substrate. The excitation of surface plasmon polaritons (SPPs) in metal substrate significantly enhanced the light absorption in graphene, while the extremely low radiative damping of SPPs resulted in an ultra-narrow absorption bandwidth of merely several nanometers. Furthermore, by applying an external electric bias to dynamically tune the Fermi energy of graphene, the ultra-narrowband absorption achieved a near-perfect modulation depth of 100 %. This work has potential applications for graphene-based electro-optic modulators in the optical communication system.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418181"},"PeriodicalIF":2.8,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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, a novel green-emitting fluorapatite phosphor Ca9Tb(PO4)5(SiO4)F2:Ce3+ (CTPSF:Ce3+), which features excellent luminous efficiency and thermal stability, was first designed and prepared. High-concentration doping of Tb3+ enables efficient green emission. Moreover, photoluminescence (PL) spectra and diffuse reflectance spectra reveal that the introduction of Ce3+ extends the excitation spectrum to the range spanning 200 nm–380 nm, with a significant improvement in efficiency, which stem from the Ce3+ → Tb3+ energy transfer process. The introduction of Ce3+ boosts the photoluminescence intensity of CTPSF by 2.315-fold, delivering a great internal quantum efficiency (IQE) of 73.95 % and an external quantum efficiency (EQE) of 57.86 %. Additionally, the thermal stability improved from retaining 66.3 % of the original intensity at 150 °C to 83.6 % retention of its original intensity at 150 °C. Finally, White-light-emitting diode (WLED) devices were fabricated by employing BaMgAl10O17:Eu2+ (blue), CaAlSiN3:Eu2+ (red), and the synthesized CTPSF:Ce3+ (green) phosphors. Upon applying a forward bias current of 60 mA, the WLED device displayed a high color rendering index (Ra) of 92.7 and a low correlated color temperature (CCT) of 3973 K, validating the potential of this green-emitting phosphor for practical applications in WLED lighting systems.
{"title":"Preparation and photoluminescence of high-monochromaticity green-emitting Ca9Tb(PO4)5(SiO4)F2:Ce3+ phosphor with high quantum efficiency and excellent thermal stability for WLEDs application","authors":"Qihao Zhou, Zhiyu Qin, Langping Dong, Jingshan Hou, Yongzheng Fang","doi":"10.1016/j.physb.2025.418177","DOIUrl":"10.1016/j.physb.2025.418177","url":null,"abstract":"<div><div>In this study, a novel green-emitting fluorapatite phosphor Ca<sub>9</sub>Tb(PO<sub>4</sub>)<sub>5</sub>(SiO<sub>4</sub>)F<sub>2</sub>:Ce<sup>3+</sup> (CTPSF:Ce<sup>3+</sup>), which features excellent luminous efficiency and thermal stability, was first designed and prepared. High-concentration doping of Tb<sup>3+</sup> enables efficient green emission. Moreover, photoluminescence (PL) spectra and diffuse reflectance spectra reveal that the introduction of Ce<sup>3+</sup> extends the excitation spectrum to the range spanning 200 nm–380 nm, with a significant improvement in efficiency, which stem from the Ce<sup>3+</sup> → Tb<sup>3+</sup> energy transfer process. The introduction of Ce<sup>3+</sup> boosts the photoluminescence intensity of CTPSF by 2.315-fold, delivering a great internal quantum efficiency (IQE) of 73.95 % and an external quantum efficiency (EQE) of 57.86 %. Additionally, the thermal stability improved from retaining 66.3 % of the original intensity at 150 °C to 83.6 % retention of its original intensity at 150 °C. Finally, White-light-emitting diode (WLED) devices were fabricated by employing BaMgAl<sub>10</sub>O<sub>17</sub>:Eu<sup>2+</sup> (blue), CaAlSiN<sub>3</sub>:Eu<sup>2+</sup> (red), and the synthesized CTPSF:Ce<sup>3+</sup> (green) phosphors. Upon applying a forward bias current of 60 mA, the WLED device displayed a high color rendering index (Ra) of 92.7 and a low correlated color temperature (CCT) of 3973 K, validating the potential of this green-emitting phosphor for practical applications in WLED lighting systems.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"724 ","pages":"Article 418177"},"PeriodicalIF":2.8,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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