Article
Materials Science, Multidisciplinary
Rufei Zhang, Chenchao Xu, Licheng Fu, Yilun Gu, Guoxiang Zhi, Jinou Dong, Xueqin Zhao, Lingfeng Xie, Haojie Zhang, Chao Cao, Fanlong Ning
Summary: The influence of chemical pressure on the ferromagnetic ordering in (La0.9Ca0.1)(Zn0.9Mn0.1)AsO magnetic semiconductor is investigated by substituting Sb for As and Y for La. X-ray diffraction measurements reveal that Sb substitution expands the lattice and introduces negative chemical pressure, while Y substitution reduces the unit-cell volume and enhances the Curie temperature by approximately 30% at a doping level of 7.5%.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Condensed Matter
Zengyao Wang, Qingyun Wu, Lei Shen
Summary: In this study, the magnetic properties and gas-sensing capabilities of 3d transition-metal (TM) doped e-phosphorene were systematically investigated using first-principles calculations. The results show that Sc, Ti, V, Cr, Mn, Fe, and Co dopants induce spin polarization with magnetic moments up to 6 μB, which arise from the exchange and crystal-field splitting of the 3d orbitals. Among them, V-doped e-phosphorene exhibits the highest Curie temperature.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Physical
J. A. Sarmiento Vanegas, J. A. Cuervo Farfan, C. E. Deluque Toro, D. A. Landinez Tellez, J. Roa-Rojas
Summary: This work reports the synthesis and characterization of SmFe0.5Co0.5O3 material, including its crystallographic, optical, electrical, and magnetic properties. The material exhibits an orthorhombic crystal structure with a disordered distribution of Fe and Co cations. It shows a bandgap of Eg = 1.0 eV, typical of semiconductor materials, and exhibits antiferromagnetic behavior at low temperatures with weak ferromagnetic response.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Xiaoxiao Duan, Xuemei Chen, Dingzhang Wu, Chunjiang Lu, Xinpeng He, Shuming Ye, Feng Lin, Rongfei Wang, Chong Wang
Summary: Dilute magnetic MnGe quantum dots (QDs) have been widely studied for their potential applications in spintronics. However, their practical use at room temperature is limited due to the relatively low Curie temperature. In this study, Te-doped Mn0.064Ge0.895Te0.041/Si QDs were successfully prepared using the ion beam composite target sputtering technique. The growth temperature and deposition thickness were found to affect the density and magnetic properties of the QDs. The Te-doped QDs exhibited higher Curie temperature and magnetization due to the enhanced exchange coupling between holes and Mn atoms.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Crystallography
Lingsheng Ke, Long Meng, Sheng Fang, Chun Lin, Mingtian Tan, Tao Qi
Summary: This study investigated the effects of rare earth (RE) lanthanum (La) and yttrium (Y) doping on the microstructures and high-temperature oxidation resistance of high-entropy alloys (HEAs). The results showed that doping La and Y decreased the oxidation resistance of the alloys due to their reaction with the matrix metal, leading to a loose oxide layer and accelerated diffusion of elements.
Article
Materials Science, Multidisciplinary
Guangqiang Mei, Wei Tan, Xingxia Cui, Cong Wang, Qing Yuan, Yafei Li, Cancan Lou, Xuefeng Hou, Mengmeng Zhao, Yong Liu, Wei Ji, Xiaona Zhang, Min Feng, Limin Cao
Summary: Researchers have achieved room-temperature ferromagnetism by doping Fe into SnSe. This ferromagnetic semiconductor has a large bandgap and may be applied in next-generation information device technologies, with the advantage of scalability for industrial production.
MATERIALS TODAY PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Imran Khan, Javed Ahmad, Muhammad Ehsan Mazhar, Jisang Hong
Summary: By utilizing the magnetic proximity effect and biaxial strain, the magnetic ground state, band gap enhancement, and valley polarization in WSe2/CrSnSe3 heterostructures can be controlled. Different magnetic anisotropy and Curie temperatures were observed in pristine and strained structures. Strain also enhanced valley splittings, providing a potential method to tune the valley splitting in the heterostructures.
Article
Chemistry, Multidisciplinary
Zhong Lin, Bevin Huang, Kyle Hwangbo, Qianni Jiang, Qi Zhang, Zhaoyu Liu, Zaiyao Fei, Hongyan Lv, Andrew Millis, Michael McGuire, Di Xiao, Jiun-Haw Chu, Xiaodong Xu
Summary: The study on thickness-dependent magnetism of vanadium triiodide (VI3) reveals robust ferromagnetism in all thin layers, with large coercive fields even in monolayers. In contrast to other vdW magnets, VI3 shows an anomalous increase in Curie temperature as the layer number decreases, reaching a maximum of 60 K in monolayers.
Article
Engineering, Electrical & Electronic
Zulfiqar, Saeed Ur Rahman, Tahirzeb Khan, Rajwali Khan, Gulzar Khan, Shaukat Khattak, Nasir Rahman, Shahid Ali, Tang Hua
Summary: Different nanoparticles (NPs) were prepared using the co-precipitation route, with Co and Ni incorporated into the SnO2 matrix. The XRD data showed a reduction in crystallite size and an increase in oxygen vacancies concentration with higher Co content. The dielectric properties were strongly influenced by doping, with S4 NPs exhibiting the highest values for dielectric loss factor and AC conductivity.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Weiyuan Wang, Jiyu Fan, Hao Liu, Huan Zheng, Chunlan Ma, Lei Zhang, Yunbin Sun, Caixia Wang, Yan Zhu, Hao Yang
Summary: The 2D layered Cr4Te5 epitaxial films prepared by pulsed laser deposition technique exhibit ferromagnetic ordering state up to 300 K and easily achieve epitaxial growth along a single orientation of the hexagonal Al2O3 (0001) substrate.
Article
Physics, Multidisciplinary
Bawoke Mekuye, Birhanu Abera
Summary: In this paper, the ferromagnetism of diluted InFeSb magnetic semiconductors is studied without using an external magnetic field, up to 317.65 K. The spin-wave model in the system, derived from the Heisenberg Hamiltonian using the green function formalism and the Holstein-Primakoff transformation estimate, is developed. The established model is used to determine the number of magnons, dispersion, Curie temperature, susceptibility, and specific heat capacity of the system. The findings show that the Curie temperature of ferromagnetic In0.893Fe0.107Sb is significantly higher than previous investigations (317.65 K).
FRONTIERS IN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Wenhui Wan, Na Kang, Yanfeng Ge, Yong Liu
Summary: In this study, the structural and magnetic properties of Si-doped bulk and 2D AlN were systematically investigated. It was found that Si atoms prefer to substitute Al atoms in both bulk and 2D AlN, and their behavior differs under different conditions. The results also suggest that 2D AlN doped with group IV elements has potential applications in spintronic devices.
FRONTIERS IN PHYSICS
(2022)
Article
Physics, Condensed Matter
Wenhui Wan, Rui Zhao, Yanfeng Ge, Yong Liu
Summary: In this study, the electronic and magnetic properties of a Janus structure based on a 2D graphene material were investigated using first-principles calculations. It was found that the Janus V2AsP has a narrow band gap of 0.21 eV and exhibits intrinsic ferromagnetic semiconductor behavior. The band gap and magnetic anisotropy can be increased by applying strain, which is important for the design of magnetic semiconductors.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Physics, Applied
Mu Lan, Rong Wang, Yu Song, Su-Huai Wei
Summary: The difficulty of increasing the Curie temperature Tc of magnetic semiconductors such as (Ga,Mn)As above room temperature is due to the p-type doping bottleneck. To overcome this bottleneck, we investigated the doping properties of Mn in GaAs using hybrid functional calculations and proposed strategies to improve the p-type dopability in (Ga,Mn)As. We found that tensile strain and high temperature quenching are effective approaches to enhance p-type doping in epitaxial (Ga,Mn)As.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Chen Li, Ke Liu, Dequan Jiang, Cheng Jin, Tianyao Pei, Ting Wen, Binbin Yue, Yonggang Wang
Summary: This study reports materials with negative, zero, and positive thermal expansion behaviors, which are hexagonal CrTe, monoclinic Cr3Te4, and trigonal Cr5Te8 in NiAs-type defective Cr1-delta Te. These materials show obvious anisotropic thermal expansion and the properties are confirmed to be originated from the magnetovolume effect through magnetic measurements. The materials with similar compositions but different structures provide a new research direction for tuning the negative thermal expansion properties of materials and searching for materials with zero thermal expansion.
INORGANIC CHEMISTRY
(2022)
Review
Chemistry, Physical
Yoshiyuki Ohtsubo, Shin-ichi Kimura, Fumitoshi Iga
Summary: This article reviews the peculiar metallic electronic states proposed and observed in Kondo insulators, and the importance of topological Kondo insulators. The controversial conclusions from experimental studies of these states are mainly due to the difficulty and inhomogeneity of the single crystal surfaces of the TKI candidates. Recent progress in forming homogeneous and well-defined clean surfaces has provided a better understanding of the surface electronic states in SmB6 and YbB12.
ELECTRONIC STRUCTURE
(2022)
Article
Physics, Applied
Bowen Qiang, Takeru Fukasawa, Tetsuya Hajiri, Takahiro Ito, Takehiko Hihara, Hidefumi Asano
Summary: The magnetic phase diagram and topological Hall effect (THE) of Co2-xPdxMo3N thin films were studied using magnetization and transport measurements. The research reveals a rich phase diagram in the temperature versus Pd content x plane, with different magnetic behaviors and a low-temperature phase found in different regions. Particularly, a prominent topological Hall effect was observed in films with certain Pd content.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Multidisciplinary Sciences
Yoshiyuki Ohtsubo, Toru Nakaya, Takuto Nakamura, Patrick Le Fevre, Francois Bertran, Fumitoshi Iga, Shin-Ichi Kimura
Summary: The breakdown of in-plane rotation symmetry in topological surface states (TSSs) of SmB6 is shown to be related to the importance of surface atomic structure. Experimentally, it is found that TSSs are anisotropic and lack the fourfold rotation symmetry observed in the bulk on the SmB6(001)-p(2 x 2) surface. These results suggest that engineering the surface atomic structure could provide a new pathway to tailor various properties of TSSs.
NATURE COMMUNICATIONS
(2022)
Article
Crystallography
Hidetoshi Miyazaki, Shin-ichi Kimura, Kensuke Onishi, Takehiko Hihara, Masato Yoshimura, Hirofumi Ishii, Masashi Mikami, Yoichi Nishino
Summary: This study investigates the thermoelectric conversion properties of Heusler-type Ru2VAl, a candidate material for next-generation thermoelectric conversion, through first-principle calculations and direct experimental observations. The results show that Ru2VAl has a wider pseudogap near the Fermi level compared to Fe2VAl, indicating a higher thermoelectric conversion performance at higher temperatures.
Article
Materials Science, Multidisciplinary
Tomo-o Terasawa, Kazuya Matsunaga, Naoki Hayashi, Takahiro Ito, Shin-ichiro Tanaka, Satoshi Yasuda, Hidehito Asaoka
Summary: This study presents angle-resolved photoemission spectroscopy and density functional calculation of graphene on a Hex-Au(001) surface. It is found that hybridization between graphene and gold leads to the generation of a bandgap and potential spin injection. The one-dimensional potential of graphene is too small to modify its electronic structure, but a bandgap of 0.2 eV is observed at the crossing point of graphene pi and Au 6sp bands.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Physics, Applied
Yuzuki Ono, Hojun Im
Summary: Thermal annealing is an effective method to improve the efficiency of a graphene/n-Si Schottky junction solar cell. The underlying mechanism was investigated through comparative studies on the removal of PMMA residues and measurement of J-V characteristics, transient photocurrent, and photovoltage. The results revealed that trap states originating from PMMA residues caused significant photocurrent leakage as the intensity of incident light increased. Thermal annealing effectively removed these undesirable residues, reducing photocurrent leakage and increasing stability.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Multidisciplinary
Hojun Im, Masataka Iwataki, Masanori Tsunekawa, Takao Watanabe, Hitoshi Sato, Masashi Nakatake, Shin-ichi Kimura
Summary: We have studied the strong correlation effects in A-site ordered perovskites CaCu3Ti4-xRuxO12 (x = 0, 1, 3.5, and 4) using photoemission and inverse photoemission spectroscopies. The peak positions of the strongly correlated Cu 3d and Ti 3d states remain relatively unchanged in x = 0, 1, 3.5, indicating the role of Ti in retaining the strong correlation effects. However, in x = 4, the Cu 3d states split into two peaks. In addition, the localized character of Cu 3d states weakens as Ru increases, and the metal-insulator transition between x = 1 and 3.5 is observed.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Multidisciplinary
Shin-ichi Kimura, Hiroshi Watanabe, Shingo Tatsukawa, Hiroshi Tanida
Summary: CeCoSi with no local inversion symmetric crystal structure (P4/nmm) undergoes a phase transition of unknown origin (Hidden Order: HO) at around 12K (T-0) above the antiferromagnetic transition temperature (T-N = 9.4 K). Using high-precision optical reflection spectroscopy, the change in electronic structure across T-0 was investigated. The optical spectrum transformed from a typical metallic behavior above T-0 to a gap-like structure at around 15 meV below T-0.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Nanoscience & Nanotechnology
B. W. Qiang, T. Fukasawa, T. Hajiri, T. Ito, T. Hihara, H. Asano
Summary: In this study, Hall transport and non-collinear magnetoresistance (NCMR) were investigated for a chiral antiferromagnet with the filled beta-Mn-type structure. It was found that epitaxial thin films of Co2-xPdxMo3N exhibited canted antiferromagnetic behavior above room temperature, but thin films with x = 1.01 to 1.38 underwent a transition to a spin spiral state with a higher magnetic moment at lower temperatures. The low-temperature phase showed large anomalous Hall effect (AHE) and topological Hall effect (THE), indicating the formation of topological spin textures.
Article
Materials Science, Multidisciplinary
Takuto Nakamura, Toru Nakaya, Yoshiyuki Ohtsubo, Hiroki Sugihara, Kiyohisa Tanaka, Ryu Yukawa, Miho Kitamura, Hiroshi Kumigashira, Keiichiro Imura, Hiroyuki S. Suzuki, Noriaki K. Sato, Shin-ichi Kimura
Summary: The electronic structure changes on the SmS surface under K doping are investigated using core-level photoelectron spectroscopy and angle-resolved photoelectron spectroscopy. The results show that the mean valence of Sm on the surface increases from nearly divalent to trivalent states with increasing K deposition. This carrier-induced valence transition (CIVT) from Sm2+ to Sm3+ is opposite to the conventional electron doping. The excess electrons from K atoms transfer to S sites, and the liberated electrons from Sm3+ ions due to CIVT are trapped around the Sm3+ ions like local excitons.
Article
Nanoscience & Nanotechnology
Hidetoshi Miyazaki, Tetsuya Hajiri, Masaharu Matsunami, Manabu Inukai, Takahiro Ito, Shin-ichi Kimura
Summary: The electronic structure, exchange splitting energy (Delta E-EX), and ferromagnetic phase transition temperature (T-C) of single-crystalline EuO (100) ultrathin films were studied using temperature- and thickness-dependent angle-resolved photoemission spectroscopy. It was found that both Delta E-EX and T-C decreased as the film thickness decreased. The band shift showed opposite thickness dependencies at the Gamma and X points, indicating the balance between hybridization of Eu 4f and O 2p states (super-exchange interaction) and that of Eu 4f, O 2p, and Eu 5d states (indirect-exchange interaction). The transition from an indirect energy gap in bulk EuO to a direct gap in ultrathin films of ferromagnetic semiconductor EuO could have potential applications in future spintronic devices.
FRONTIERS IN NANOTECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Takuto Nakamura, Yoshiyuki Ohtsubo, Ayumi Harasawa, Koichiro Yaji, Shik Shin, Fumio Komori, Shin-ichi Kimura
Summary: In this study, the spin-orbit texture in a surface Rashba system on Bi/InAs(110)-(2 x 1) was investigated, revealing odd fluctuations in the spin polarization and unexpected freedom for spin manipulation.
Article
Materials Science, Multidisciplinary
Damir Pinek, Takahiro Ito, Kanji Furuta, Arnoldus J. van Bunningen, Patrick Le Fevre, Francois Bertran, Thierry Ouisse
Summary: In this experimental study using ARPES, the electronic states of the nanolamellar compound Ti2SnC were investigated. The observed Fermi surface is formed by a combination of quasi-two-dimensional corrugated tubes and quasi-one-dimensional thin plates, with a clear Dirac-like dispersion and an evanescent surface state.
