Advances in Condensed Matter Physics

Journal Information
ISSN / EISSN : 2326-3512 / 2326-3520
Published by: Hans Publishers (10.12677)
Total articles ≅ 105
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刘 博
Advances in Condensed Matter Physics, Volume 11, pp 21-27; https://doi.org/10.12677/cmp.2022.112003

Abstract:
The transition metal phosphorus trisulfides FePSe3 was successfully grown by chemical vapor transport (CVT) method. The chemical composition, crystal structure, electrical transport properties, and magnetic anisotropy have been studied by scanning electron microscope-energy dispersion spectrum (SEM-EDX), X-ray diffractometer (XRD), physical property measurement system (PPMS), and magnetic property measurement system (MPMS). Single crystal and powder X-ray diffraction pattern confirms that FePSe3 belongs to the trigonal crystal structure, and has the features of van der Waals layer structure. The in-plane resistivity increases with decreasing temperature and exhibits semiconductor behavior with an activation energy of 268 meV. In high temperature, the in-plane and out-of-plane magnetic susceptibility increase with decreasing temperature and exhibit Curie-Weiss paramagnetic behavior, but the Weiss temperatures of both directions have a different sign which indicates that the magnetic properties of FePSe3 are anisotropic. With decreasing temperature, the magnetic susceptibility of both directions shows a sharp decrease at the temperature of 109 K and then almost keeps a constant, which is a typical antiferromagnetic transition, but further analysis suggests that the antiferromagnetic transition is a first-order phase transition.
慧陈 佳
Advances in Condensed Matter Physics, Volume 11, pp 49-56; https://doi.org/10.12677/cmp.2022.112006

Abstract:
Based on two-band Bogoliubov-de Gennes theory, we study the boundary effect of an interface between two-band superconductor and insulator (or vacuum). New boundary terms are introduced into two-band Ginzburg-Landau free energy, and the characteristic length scale of boundary effect can be estimated. Taking into account this boundary effect, we study the critical temperature dependence of film thickness for magnesium diboride. Our numerical results are in good agreement with the experimental data measured in this material.
超刘 希
Advances in Condensed Matter Physics, Volume 11, pp 38-48; https://doi.org/10.12677/cmp.2022.112005

Abstract:
Using first-principles calculations, we investigate the effect of zigzag extensions on the magnetic properties of triangular graphene quantum dot with armchair edges. The results show that when two or three zigzag extensions are added to the armchair edges of triangular graphene quantum dot, the ground states of most modified structures conform to the Lieb’s theorem, while some structures violate the Lieb’s theorem, which can be attributed to the small energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). In addition, we find that the ground states of partial modified structures remain in the low-spin state, while the others change from a low-spin state to a high-spin state. Our findings have important im-plications for manipulating the magnetism of graphene quantum dot with armchair edges.
馨王 兰
Advances in Condensed Matter Physics, Volume 11, pp 28-37; https://doi.org/10.12677/cmp.2022.112004

Abstract:
Previous studies have shown that AlFeTiCrZnCu high entropy alloys (HEAs) are simple cubic crystal structure. In order to future study the effect of Ti content on high entropy alloys, the lattice parameter, mass density, elastic constant, elastic modulus, and the heats of formation for the high entropy alloys AlFeTixCrZnCu with the different Ti content were studied by density functional theory of first principle and plane-wave pseudopotential technique with generalized gradient approximation (GGA). The crystal structure was built with the Virtual Crystal Approximation (VCA). The calculated results indicate that the lattice parameter of HEA AlFeTixCrZnCu increases with the increasing mole fraction of Ti, and the mass density decreases. The mechanical stability of HEA AlFeTixCrZnCu can be improved with the increase of Ti. The brittleness/toughness of HEA AlFeTixCrZnCu also varies with the content of Ti or the brittleness/toughness criterion. The system stability and thermodynamic stability of HEA AlFeTixCrZnCu did not change with the increase of Ti, but only decrease.
彤江 晓
Advances in Condensed Matter Physics, Volume 11, pp 13-20; https://doi.org/10.12677/cmp.2022.112002

Abstract:
Graphene is a lamellar structure of graphite and it is one of important research objects in the current materials and condensed matter disciplines. It has a wide range of development prospect due to its unique structure and excellent properties. Therefore, the research on the physical properties of graphene has become a particularly important part of the present. In this study, the molecular dynamics method was mainly used to simulate the dynamic process of bending vibration of graphene nanoribbons after compressive deformation. The effects of structure size, temperature, rotation angle and layer rotation mode on the vibration frequency of the graphene nanoribbon were studied. The simulation results demonstrate that the resonant frequency of graphene nanoribbons always fluctuates to a certain extent with the changes in its structure size, temperature, rotation angle and layer rotation mode, and the length is the most important factor affecting the vibration frequency of graphene nanoribbons. And the number of the layer, temperature, rotation angle and layer rotation mode have a certain influence on the vibration frequency, which is influenced slightly by the width of the nanoribbon.
刘 鑫
Advances in Condensed Matter Physics, Volume 11, pp 1-11; https://doi.org/10.12677/cmp.2022.111001

Abstract:
The rapid growth of the lithium-ion battery market has led to higher requirements for the performance and stability of lithium-ion batteries. Traditional liquid organic batteries are prone to short-circuits and cause explosions and fires, posing serious safety hazards. Compared with traditional Li-ion batteries using liquid electrolytes, all-solid-state Li-ion batteries have received extensive attention due to their good stability and safety. Garnet-type solid electrolyte Li7La3Zr2O12 (LLZO) has high ionic conductivity and is considered to be a promising solid electrolyte. However, the synthesis of LLZO often requires high temperature, but the high temperature could lead to a large amount of lithium evaporation, thus reducing the ionic conductivity of the LLZO-based samples. Therefore, how to reduce the synthesis temperature of LLZO and improve its ionic conductivity is an important topic. Here, we synthesized solid electrolytic Li6.1Ga0.3La3Zr2O12 with garnet-type structure by traditional solid-phase method and introducing Al2O3 as a sintering aid. Compared with the samples without sintering aid, the introduction of Al2O3 not only reduces the sintering temperature, but also significantly increases the ionic conductivity. It is found that adding a small amount of Al2O3 as an additive can reduce the sintering temperature from 1100°C to around 1050˚C. Finally, we found, when the Al2O3 content is 2 wt%, the room-temperature ionic conductivity is the highest at 1.28 mS/cm.
婷唐 婷
Advances in Condensed Matter Physics, Volume 11, pp 57-64; https://doi.org/10.12677/cmp.2022.113007

Abstract:
The band structure and quantum phase transition of graphene/hexagonal boron nitride heterojunction (h-BN) under local potentials are studied by the tight-binding method. The result shows that the graphene layer is in the quantum spin Hall state and the h-BN layer is in the insulating state when the intrinsic spin-orbit coupling strength of the graphene layer is given. As the local potential of the graphene layer increases, the system will change from a quantum spin Hall state to a semiconductor state. New gapless edge states can be generated by tuning the local potential of the h-BN layer, so that the quantum spin Hall state of the graphene layer becomes the quantum spin Hall state composed of the edge states within and between layers.
高 贝
Advances in Condensed Matter Physics, Volume 10, pp 9-14; https://doi.org/10.12677/cmp.2021.101002

Abstract:
过渡金属硫化物(TMDCs)是一种受到国内外学者广泛关注的新型二维材料,尤其是它与一些二维层状材料构成的异质结进一步拓展了其在新型光电器件领域的应用。本文综述了近几年通过第一性原理方法研究外电场对单层及双层TMDCs(MoS2,MoSe2,MoTe2,WS2)、两种或者多种TMDCs组建的异质结、TMDCs与BNC型二维层状材料(g-C3N4、g-C2N、BC3和C3N)组建的异质结、TMDCs与石墨烯组建的异质结等材料体系的能带特性的影响。研究表明适当的外电场可以有效地调控TMDCs材料及其异质结的能带结构、自旋极化以及电荷转移,从而使得TMDCs材料及其异质结在光电器件领域有着重要的应用。 Transition-metal dichalcogenides (TMDCs) is one of extensive attention by international and domestic academics of new 2D materials, especially with heterojunctions consists of some two-dimensional layered materials to expand its application in the electronic and photonic devices fields. In this letter we review the latest research advances which the external electric fields control energy band characteristics of monolayer and bilayer TMDCs materials (MoS2, MoSe2 MoTe2, WS2), van der Waals (vdW) heterojunctions composed of multiple TMDCs materials, vdW heterojunctions composed of B, N and C type two-dimensional layered materials (g-C3N4, g-C2N, BC3 and C3N) and TMDCs materials, vdW heterojunctions composed of TMDCs and graphene by the first-principles calculations. These studies suggest that the appropriate external electric field can effectively regulate the energy band, spin polarization and charge transfer of TMDCs materials and its heterojunctions which is beneficial to the application in the optical, electronic and optoelectronic field.
刚宋 叶
Advances in Condensed Matter Physics, Volume 10, pp 56-65; https://doi.org/10.12677/cmp.2021.102007

Abstract:
本文使用第一性原理计算方法研究了极性苯分子4-氰基苯胺和4,5-二氨基邻苯二腈夹钒原子三明治团簇的结构和磁学性质。计算结果表明三明治团簇中极性苯分子以反铁电形式排列,且钒–钒平均间距随着分子层数的增加显著减小。团簇的热力学稳定性随着分子层数的增加逐渐减小,但迅速趋于平稳。极性苯分子构成的团簇呈现半金属或者是金属性质,而它们的磁基态及其稳定性强烈地依赖于分子层数,这与苯分子构成的团簇存在很大的差异。本文的研究结果对于调控有机分子和过渡金属原子复合物的磁电特性具有重要的借鉴作用。 In this paper, the structural and magnetic properties are studied by the first-principle method for the sandwich clusters consisted of polar benzene molecules 4-cyananiline and 4, 5-diamino-phthalonitrile with vanadium. The calculated results show that the polar benzene molecules in the sandwich cluster are arranged in the antiferroelectric form, and the average vanadium-vanadium spacing decreases significantly with the increase of molecular layer number. The thermal stability of the cluster decreases gradually with the increase of molecular layer number, but tends to be stable rapidly. The clusters containing polar molecules exhibit a half-metallic or metallic property, and their magnetic ground states, as well as their stability, are strongly dependent on the number of molecular layers, which is very different from those containing benzene molecule. The results of this study are useful for regulating the magnetoelectric properties of organic molecules and transition metal complexes.
源黄 培
Advances in Condensed Matter Physics, Volume 10, pp 87-93; https://doi.org/10.12677/cmp.2021.104011

Abstract:
When the magnetic moment lined order in the magnetic materials generates collective movement, we call this phenomenon as spin wave. The spin wave that not only has momentum but also has orbital angular momentum in the propagation process is called twisted spin wave. Different from the plane wave, twisted spin wave will twist alone the central axis during its propagating. Finally, the twisted spin wave will distribute in spiral way, meanwhile the spin wave always possesses angular momentum. This paper studies eigenmodes of twisted spin waves in ferromagnetic nanocylinder; through applying a sinc pulse magnetic field in the bottom of the nanocylinder and using FFT, analyzes the component of dynamic magnetic moment; and gets the resonant spectrum of twisted spin waves. Then we use inverse Fast Fourier Transform to acquire the mode of twisted spin wave with l = 1. Moreover, by applying an in-plane rotating field, a twisted spin wave with topological charge l = 1 can be excited.
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