共查询到20条相似文献,搜索用时 62 毫秒
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电荷转移能级和缺陷形成能的计算对探索半导体材料的n型和p型掺杂效率具有重要的指导意义。基于第一性原理方法,结合二维带电缺陷计算理论,系统计算了二维类石墨烯氮化铝(graphene-like AlN, g-AlN)中四种(C_Al,Si_Al,Ge_Al,Sn_Al)可能的n型掺杂体系的结构、磁学、电学以及缺陷性质。结果表明,四种体系的最稳定价态均为+1价和0价,Sn_Al具有较深的施主能级,不具备为二维g-AlN提供n型载流子的条件,而C_Al,Si_Al,Ge_Al表现为浅能级施主特性,均能在一定条件下成为理想的施主杂质,其中Si_Al具有最浅的施主特性以及最低的缺陷形成能,因而是二维g-AlN中实现n型掺杂的首选掺杂剂。另外,在p型二维g-AlN中,四种掺杂原子都会成为有效的空穴捕获中心,严重降低p型载流子导电率。研究数据将会为实验上实现二维g-AlN n型掺杂提供理论解释和指导。 相似文献
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以芥子气和沙林为代表的毒剂具有毒性强、扩散快的特点,是一类杀伤力强、难以防护的化学战剂,对其快速高效检测是一项具有挑战性的课题.本文基于第一性原理计算方法研究了V掺杂对二维MoS_2气敏性能影响的机理,发现V原子向二维MoS_2的掺杂过程为自发的放热反应, V原子可以稳定掺杂于二维MoS_2超胞结构中的S空位上.掺杂进入二维MoS_2体系的V原子作为施主中心向周围Mo原子给出电子,从而提高了材料的导电能力.吸附能、吸附距离和吸附过程中的电子转移计算结果表明V的掺杂提高了二维MoS_2对气体分子的吸附能力,增强了吸附质分子与基底表面的电子相互作用,从而提高了二维MoS_2的气敏性能. 相似文献
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通过第一性原理赝势平面波方法研究了氢原子在B2-NiAl和Cr合金中的占位以及对键合性质的影响. H在NiAl的富Al和富Ni八面体间隙杂质形成能分别为-2.365和-2.022eV,而在四面体间隙不稳定. H在Cr的八面体和四面体间隙的杂质形成能分别为-2.344和-2.605eV. H在NiAl中的最稳定位置为富Al八面体间隙,而在Cr中的最稳定位置是四面体间隙. 可以预期H在B2-NiAl/Cr体系中主要占据Cr 的四面体间隙位置. 通过分析原子结构、电荷集居数、价电荷密度以及态密度,讨论了H对B2
关键词:
NiAl/Cr双相合金
H原子
第一性原理 相似文献
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本文基于密度泛函理论(DFT)的第一性原理计算了W、Mn、V、Ti替位掺杂二维MoSi2N4后的几何结构、电子结构以及光学性质的变化.电子结构分析表明W、Mn、W、Ti替位掺杂二维MoSi2N4后的禁带宽度分别为1.806 e V、1.003 e V、1.218 e V和1.373 e V;四种过渡金属掺杂后MoSi2N4的带隙类型没有发生改变,均为间接带隙半导体;W掺杂后的杂质能级靠近价带顶,费米能级靠近价带顶,为p型半导体,杂质能级为受主能级;Mn掺杂后的杂质能级靠近导带底,费米能级靠近导带底,为n型半导体;V和Ti掺杂后杂质能级位于费米能级附近,为复合中心;光学性质分析表明,在2 e V~4 e V的能量区间内,W掺杂结构的吸收波长为336 nm,体系发生红移;Mn、V和Ti替位掺杂后的吸收波长分别为320 nm、358 nm和338 nm,且掺杂体系均发生蓝移. 相似文献
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本文提出了一种在二维SnSe中掺杂一维Mn纳米线的2D-1D复合结构,并系统地研究了其热电性能。结果表明,一维Mn纳米线将电子态汇聚在纳米线附近,提高了材料的各向异性,降低了电子在某一方向上的散射效应,导致了较高的迁移率和电导率。自旋向上和向下的电子态发生简并,导致了较高的塞贝克系数和电导率。此外,Mn纳米线将晶格热导率降低了约0.17 W·m?1·K?1。在200至650 K的温度范围内,3Mn-SnSe具有0.73至3.78的极高ZT值,比本征二维SnSe平均提高了约39.2%。 相似文献
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本文提出了一种在二维SnSe中掺杂一维Mn纳米线的2D-1D复合结构,并系统地研究了其热电性能。结果表明,一维Mn纳米线将电子态汇聚在纳米线附近,提高了材料的各向异性,降低了电子在某一方向上的散射效应,导致了较高的迁移率和电导率。自旋向上和向下的电子态发生简并,导致了较高的塞贝克系数和电导率。此外,Mn纳米线将晶格热导率降低了约0.17 W·m?1·K?1。在200至650 K的温度范围内,3Mn-SnSe具有0.73至3.78的极高ZT值,比本征二维SnSe平均提高了约39.2%。 相似文献
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Yuxin Cai Muhammad Faizan Huimin Mu Yilin Zhang Hongshuai Zou Hong Jian Zhao Yuhao Fu Lijun Zhang 《Frontiers of Physics》2023,18(4):43303
Two-dimensional layered materials (2DLMs) have attracted growing attention in optoelectronic devices due to their intriguing anisotropic physical properties. Different members of 2DLMs exhibit unique anisotropic electrical, optical, and thermal properties, fundamentally related to their crystal structure. Among them, directional heat transfer plays a vital role in the thermal management of electronic devices. Here, we use density functional theory calculations to investigate the thermal transport properties of representative layered materials: β-InSe, γ-InSe, MoS2, and h-BN. We found that the lattice thermal conductivities of β-InSe, γ-InSe, MoS2, and h-BN display diverse anisotropic behaviors with anisotropy ratios of 10.4, 9.4, 64.9, and 107.7, respectively. The analysis of the phonon modes further indicates that the phonon group velocity is responsible for the anisotropy of thermal transport. Furthermore, the low lattice thermal conductivity of the layered InSe mainly comes from low phonon group velocity and atomic masses. Our findings provide a fundamental physical understanding of the anisotropic thermal transport in layered materials. We hope this study could inspire the advancement of 2DLMs thermal management applications in next-generation integrated electronic and optoelectronic devices. 相似文献
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近年来,二维材料优异的摩擦特性成为人们关注的焦点,然而目前缺乏理论上对其摩擦力进行快速、有效、精确的计算预测方法.本文提出采用密度泛函理论计算真实体系的滑动势能面,利用得到的"数值型势能面"替代传统的解析势函数,并结合Prandtl-Tomlinson模型,量化求解具有复杂形状势能面的真实二维材料体系的摩擦行为.基于该方法,揭示了原子力显微镜实验中观察到的石墨烯Moire纹超晶格结构的双周期"黏-滑"摩擦现象;理论预测了二维材料异质结构的层间超低摩擦现象,相对于同质材料,其静摩擦力和滑动摩擦力均成数量级降低,发现势能面起伏和驱动弹簧刚度均会影响层间相对滑动路径,进而对层间的摩擦行为产生影响.该方法同样可拓展到其他van der Waals作用主导的界面摩擦体系. 相似文献
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Two-dimensional(2D) materials, such as graphene, phosphorene, and transition metal dichalcogenides(e.g., Mo S2 and WS2), have attracted a great deal of attention recently due to their extraordinary structural, mechanical, and physical properties. In particular, 2D materials have shown great potential for thermal management and thermoelectric energy generation. In this article, we review the recent advances in the study of thermal properties of 2D materials. We first review some important aspects in thermal conductivity of graphene and discuss the possibility to enhance the ultra-high thermal conductivity of graphene. Next, we discuss thermal conductivity of Mo S2 and the new strategy for thermal management of Mo S2 device. Subsequently, we discuss the anisotropic thermal properties of phosphorene. Finally, we review the application of 2D materials in thermal devices, including thermal rectifier and thermal modulator. 相似文献
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Giant Rashba-like spin-orbit splitting with distinct spin texture in two-dimensional heterostructures 下载免费PDF全文
Jianbao Zhu 《中国物理 B》2021,30(8):87307-087307
Based on first-principles density functional theory calculation, we discover a novel form of spin-orbit (SO) splitting in two-dimensional (2D) heterostructures composed of a single Bi(111) bilayer stacking with a 2D semiconducting In2Se2 or a 2D ferroelectric α-In2Se3 layer. Such SO splitting has a Rashba-like but distinct spin texture in the valence band around the maximum, where the chirality of the spin texture reverses within the upper spin-split branch, in contrast to the conventional Rashba systems where the upper branch and lower branch have opposite chirality solely in the region below the band crossing point. The ferroelectric nature of α-In2Se3 further enables the tuning of the spin texture upon the reversal of the electric polarization with the application of an external electric field. Detailed analysis based on a tight-binding model reveals that such SO splitting texture results from the interplay of complex orbital characters and substrate interaction. This finding enriches the diversity of SO splitting systems and is also expected to promise for spintronic applications. 相似文献
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自石墨烯发现以来,大量二维层状材料被相继发现.二维材料中载流子被限制在界面1 nm空间内,使其对化学掺杂非常敏感,有望引起生物传感领域的技术变革.生物传感过程无论基于何种传感机制,都包含了检测物识别和信号转化过程.检测物识别通常依靠传感界面的生物探针来完成,信号转换依靠二维材料来实现信号输出.在传感界面处对生物探针和二维材料进行原子级精准构筑,则可精确调控传感过程中的物理化学过程,优化器件的各项指标.本文综述了二维生物传感界面构筑领域的研究进展,重点介绍了目前几种常见的二维生物传感器的传感机制和不同类型的生物探针精准构筑方法,探讨了未来生物传感界面研究的发展方向. 相似文献
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First principles calculations of relationship between the Cu surface states and relaxations 下载免费PDF全文
In this paper the relationship between the surface relaxations and the electron
density distributions of surface states of Cu(100), Cu(110), and Cu(111)
surfaces is obtained by first-principles calculations. The calculations
indicate that relaxations mainly occur in the layers at which the surface
states electrons are localized, and the magnitudes of the multilayer
relaxations correspond to the difference of electron density of
surface states between adjacent layers. The larger the interlayer relaxation
is, the larger the difference of electron density of surface states between
two layers is. 相似文献
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First-principles investigation of chemical modification on two-dimensional iron–phthalocyanine sheet 下载免费PDF全文
Successful synthesis of single iron–phthalocyanie(FePc) framework layer on substrate and its transferrable properties open the door for decorating the separately distributed transition metals for exploring the diverse properties. We have studied the effects of chemical modification on two-dimensional FePc organometallic framework with density functional theory. For simplicity, the non-metal atoms with variant valence electrons are used as prototypes to estimate the effects from chemical modifications with different functional groups. The thermo-stabilities of the non-metal atom decorated complex sheet materials have been estimated by the first-principles constant energy molecular dynamic simulations. Upon the nonmetal atom adsorption, the magnetic moment could be changed from 2 μBto 0, 1, 2, and 3 μBper unit cell for the case of tetra-, penta-, hexa-, and hepta-valent non-metal modifications, respectively, showing interesting promise to tailor its magnetic properties for potential applications. 相似文献