本文采用密度泛函理论框架内的第一性原理计算，研究了由 Al 和 P 共掺杂硅烯形成 AlSi$_6$P 纳米片的物理性质，例如电子、力学、热学和光学性质。本研究特别关注褶皱硅烯结构中 Al 原子与 P 原子之间的相互作用效应。我们推断该相互作用类型为吸引作用，并导致态密度不对称，从而打开带隙。与 BN 共掺杂硅烯相比，Al-P 共掺杂硅烯中的褶皱受掺杂剂影响不大，因为 Si-P 和 Al-P 的键长与 Si-Si 键长非常接近。另一方面，较长的 Si-Al 键长降低了刚度，因此使 AlSi$_6$P 在较小的外加应变值下发生断裂。AlSi$_6$P 应力-应变曲线的弹性和非弹性区域取决于 Al 和 P 原子的位置。由 Al-P 掺杂剂引起的有限带隙提高了 Seebeck 系数和品质因数，并导致介电响应及光电导中峰值发生红移。最后，本文报道了 AlSi$_6$P 介电函数实部和虚部、激发谱、折射率以及光学响应的性质。
英文摘要：
Physical quilities such as electronic, mechanical, thermal, and optical properties of Al and P codoped silicene forming AlSi$_6$P nanosheets are investigated by first-principle calculations within density functional theory. A particular attention of this study is paid to the interaction effect between the Al and P atoms in the buckled silicene structure. We infer that the interaction type is attractive and it leads to an asymmetry in the density of states opening up a band gap. In contrast to BN-codoped silicene, the buckling in the Al-P codoped silicene is not much influenced by the dopants as the bond lengths of Si-P and Al-P are very similar to the Si-Si bond lengths. On the other hand, the longer bond length of Si-Al decreases the stiffness and thus induces fractures at smaller values of applied strain in AlSi$_6$P. The elastic and nonelastic regions of the stress-strain curve of AlSi$_6$P depend on the placement of the Al and P atoms. The finite band gap caused by the Al-P dopant leads to enhancement of the Seebeck coefficient and the figure of merit, and induces a redshift of peaks in the dielectric response, and the optical conductivity. Finally, properties of the real and imaginary parts of the dielectric function, the excitation spectra, the refractive index, and the optical response of AlSi$_6$P are reported.
Electron transport properties of a narrow-bandgap semiconductor Bi$_2$O$_2$Te nanosheet
采用机械剥离法制备了薄的窄带隙半导体Bi $_2$ O $_2$ Te纳米片，并在重掺杂Si/SiO $_2$衬底上制备了霍尔栅器件，并在低温下进行了研究。栅传输特性的测量表明，在纳米片的传输载流子的$n$型。纳米片中的载流子密度、迁移率和平均自由程通过测量霍尔电阻和霍尔条器件的纵向电阻来确定，并且发现纳米片中的电子输运处于准二维（2D）、强无序状态。在垂直于纳米片平面施加的磁场下的器件的磁输运测量显示出在低场下的主要弱反定域化（WAL）特性和在大场下的线性磁阻（LMR）行为。我们将WAL特性归因于强自旋轨道相互作用（SOI），而LMR归因于纳米片中强无序的经典起源。低场磁导率的测量也进行了分析的基础上的多通道Hikami-Larkin-Nagaoka理论与LMR校正被考虑在内。提取了纳米片中由于LMR引起的相位相干长度、自旋弛豫长度、有效二维导电沟道数和线性项系数。发现Bi $_2$ O $_2$ Te纳米片中的自旋弛豫长度比其对应物Bi $_2$ O $_2$ Se纳米片中的自旋弛豫长度小几倍，因此在Bi $_2$ O $_2$ Te纳米片中存在超强SOI。我们在这项研究中报告的结果将极大地鼓励这种新兴的窄带隙半导体2D材料的进一步研究和应用。
Outstandingly high thermal conductivity, elastic modulus, carrier mobility and piezoelectricity in two-dimensional semiconducting CrC2N4: A first-principles study
First-principles discovery of stable, anisotropic, semiconducting Sb2X2O (X = S, Se) and Janus Sb2SSeO nanosheets for optoelectronics and photocatalysis
University of Ostrava（俄斯特拉发大学）；Leibniz Universität Hannover（汉诺威莱布尼茨大学）
Boston University（波士顿大学）；University of Colorado Boulder（科罗拉多大学博尔德分校）；Massachusetts Institute of Technology（麻省理工学院）；National Institute of Standards and Technology（美国国家标准与技术研究院）；Washington State University（华盛顿州立大学）
High-temperature ferromagnetism and ferroelasticity in ultraflexible atomically thin square-shaped lattices
School of Physical Science and Technology, Southwest University（西南大学物理科学与技术学院）；School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院）；Department of Physics, Beijing Normal University（北京师范大学物理系）；School of Science, Inner Mongolia University of Technology（内蒙古工业大学理学院）；School of Physics, State Key Laboratory for Crystal Materials, Shandong University（山东大学物理学院晶体材料国家重点实验室）
