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Modulating electronic and magnetic properties of zigzag MoSe2 nanoribbons with different edge structures
摘要： In this paper, we performed the first-principles calculations to investigate the effect of different edge structures on stability, electronic and magnetic properties of zigzag MoSe2 nanoribbons and their corresponding variation by saturating the ribbon edges with H. We have taken twelve patterns of edge structure into consideration due to the chemical nonequivalence of Mo and Se atoms. We found that H-NR-u and H-NR-s have the highest stability by analysing binding energies. Specially, all of the zigzag MoSe2 nanoribbons exhibit obvious metallicity, whether they are hydrogenated or not. What's more, the pristine and hydrogenated zigzag nanoribbons have stable ferrimagnetism with a wide range of total magnetic moment 0.27–3.59 μB. The Mo-terminated nanoribbon has the largest magnetic moment and hydrogenation can significantly reduce the magnetic moment of nanoribbons. We also reveal zigzag MoSe2 nanoribbons with same terminal have very similar stability, electronic and magnetic properties, which have nothing to do with the symmetry of the system. Above all, these unique properties of zigzag MoSe2 nanoribbons have the great potential for electronic, spintronic and magnetoresistive nano-devices in the future.
关键词： Hydrogenation,Nanoribbon,Ferrimagnetism,First-principle calculation,MoSe2
更新于2025-09-23 15:23:52
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First-principle study on honeycomb fluorated-InTe monolayer with large Rashba spin splitting and direct bandgap
摘要： Rashba e?ect is much related to next-generation spintronic devices. It is highly desirable to search for Rashba materials with large Rashba spin splitting, which is considered as the key factor for the application of spin ?eld-e?ect transistor. Here, we design a two-dimensional monolayer of ?uorated-InTe (InTeF) with large Rashba spin splitting and direct bandgap on the basis of ?rst-principles calculations. InTeF monolayer is energetically and dynamically stable based on the calculations of cohesive energy and phonon dispersion. Remarkably, the Rashba parameter αR is about 1.08 eV·?, comparable to that of the BiTeI monolayer (1.86 eV·?). The direct bandgap is estimated to be 2.48 eV by HSE06 hybrid functional, which shows good prospects in light-emitting devices and photodetectors. To further explore the e?ect of substrates on the electronic structure of InTeF monolayer, we build two heterostructures, and the results show that the strength of Rashba e?ect and the direct bandgap nature in InTeF monolayer can be well preserved under the in?uence of substrates. Based on the above ?ndings in our work, InTeF monolayer is considered to be one of the promising 2D materials for the application of spintronics as well as optoelectronics.
关键词： Rashba spin splitting,InTeF monolayer,First-principle calculation,Direct bandgap
更新于2025-09-23 15:22:29
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High performance and mechanism of the resistive switching device based on lead halide thin films
摘要： In this work, the lead halide was firstly applied in resistive random-access memory (RRAM) device with the structure of W/lead iodide/fluorine-doped tin oxide (FTO). The mechanism was investigated by reliable data fitting and the experiment of temperature influence, illustrating that the resistive switching phenomenon was origin from the filament. The iodide vacancies were considered as the main composition of the conductive filaments, which was verified by the first principle calculation and experimental verification. These performances were also found in device fabricated by other lead halide, such as PbBr2 and PbCl2. Moreover, they performed great potential as the non-volatile memory due to the excellent resistive switching properties. This work was of great significance for the expansion of RRAM material system.
关键词： conductive filaments,lead halide,resistive switching memory,first principle calculation
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field emission patterns from carbon nanotubes calculated by time-dependent density functional theory
摘要： We calculated the field emission patterns of various types of carbon nanotubes (CNTs). Regarding the near field regime, emission patterns of CNTs and hydrogen terminated CNTs (H-CNTs) well corresponds to the atoms located in the tube tip. We also found different focusing features; a focused-type and an unfocused-type. The beams from armchair (5,5) and (6,6) types are focused, while the beam from zigzag (9,0) types are unfocused.
关键词： field emission,carbon nanotubes,emission pattern,time dependent density functional theory,first principle calculation,ab initio calculation
更新于2025-09-23 15:21:21
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Roles of spin-orbit coupling in tetragonal hybrid halide perovskite for photovoltaics light-absorber
摘要： Hybrid halide perovskite has been gain appropriate attraction because of their relatively high efficiency in most recently solid-state solar cell development. In this work, A first-principle calculation based on non-local van der Waals-corrected Density Functional Theory (vdW-DFT) is performed to investigate high accuracy atomic structures of a tetragonal structure methyl ammonium (CH3NH3) metal (Pb, Sn) halide (Br3, Cl3, I3). The calculated electronic structures were systematically studied using semi-local exchange-correlation functional (GGA-PBE), non-local functional (hybrid HSE06) and post-DFT approximation (GW). A relativistic effect in metal ion was taken into account by incorporating spin-orbit coupling (SOC) effect to obtain more accurate band gap properties of these materials. Our results shown that SOC corrected the electronic structures about 0.92 eV and 0.19 eV in case of lead ion and tin ion, respectively. The combination between GW approximation and spin-orbit coupling show a good agreement between DFT calculations and experimental studies. This computational scheme is necessary for high accuracy organic-inorganic solar cell design.
关键词： Spin-Orbit Coupling,Hybrid perovskite solar cell,Methyl ammonium metal halide,First-principle calculation
更新于2025-09-12 10:27:22
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Highly-efficient overall water splitting in 2D Janus group-III chalcogenide multilayers: the roles of intrinsic electric filed and vacancy defects
摘要： Two-dimensional (2D) van der Waals materials have been widely adopted as photocatalysts for water splitting, but the energy conversion efficiency remains low. On the basis of first-principles calculations, we demonstrate that the 2D Janus group-III chalcogenide multilayers: InGaXY, M2XY and InGaX2 (M = In/Ga; X, Y = S/Se/Te), are promising photocatalysts for highly-efficient overall water splitting. The intrinsic electric field enhances the spatial separations of photogenerated carriers and alters the band alignment, which is more pronounced compared with the Janus monolayers. High solar-to-hydrogen (STH) efficiency with the upper limit of 38.5% was predicted in the Janus multilayers. More excitingly, the Ga vacancy of InGaSSe bilayer effectively lowers the overpotentials of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to the levels provided solely by the photogenerated carriers. Our theoretical results suggest that the 2D Janus group-III chalcogenide multilayers could be utilized as highly efficient photocatalysts for overall water splitting without the needs of sacrificial reagents.
关键词： Photocatalytic water splitting,Janus group-III chalcogenides,Intrinsic electric fields,First-principle calculation,Solar-to-hydrogen efficiency
更新于2025-09-11 14:15:04
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Interfacial properties of Hg <sub/>2</sub> CuTi-type Heusler alloy Ti <sub/>2</sub> NiAl/GaAs(100) heterojunction
摘要： For Hg2CuTi-type Inverse-Heusler alloy Ti2NiAl/GaAs(100) tunnel heterojunction, the magnetism, density of states and spin polarization of atoms at the interface were investigated systematically based on the first-principle calculation within the density functional theory (DFT). The calculated results reveal that the interface states seriously destroy the structural half-metallicity and lead to the spin polarization less than 60%. Among all of calculational hetero-structures, only the heterojunction with TA-ATⅡ structure still retains nearly 60% spin polarization, which is expected for further application in Tunnel Magneto resistance (TMR) devices.
关键词： first-principle calculation,Hg2CuTi-type Heusler alloy,TMR devices,Ti2NiAl/GaAs(100) heterojunction,spin polarization
更新于2025-09-11 14:15:04
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First-principle calculation of the electronic structures and optical properties of the metallic and nonmetallic elements-doped ZnO on the basis of photocatalysis
摘要： In the present paper, the electronic structure and the optical properties of metallic and nonmetallic elements-doped ZnO were investigated based on the principle of photocatalysis by first-principle density functional theory. Element doping shortens the band gap of ZnO. Due to the p-type characteristics, Fe, Cu, B and N doping brings impurity states over the Fermi level of ZnO, resulting in the shortening of the band gap, extending the absorption and utilization of solar light and thus enhancing the photocatalytic properties of ZnO. However, no impurity states appear in the band gap of Cd- and S-doped ZnO due to the intrinsic doping of Cd and S. Further investigations indicate that different doping atoms can indeed alter the near-Fermi level density of states (DOS) of ZnO and their electronic structures via substitution of zinc and oxygen atoms. In addition, the optical properties of ZnO are improved after doped with different atoms by comparing with those of pure ZnO. Due to the difference of their outer shell electrons of the doped atoms, the optical absorption properties of the investigated materials are followed as the following order: Fe-/B-doped ZnO>Cu-/N-doped ZnO>Cd-/S-doped ZnO>pure ZnO.
关键词： Doped ZnO,Density functional theory (DFT),Photocatalysis,First principle calculation
更新于2025-09-11 14:15:04