We simulate the scattering of O$_2$ from Ag(111) with classical dynamics simulations performed on a six-dimensional potential energy surface calculated within semi-local density-functional theory (DFT). The enigmatic experimental trends that originally required the conjecture of two types of repulsive walls, arising from a physisorption and chemisorption part of the interaction potential, are fully reproduced. Given the inadequate description of the physisorption properties in semi-local DFT, our work casts severe doubts on the prevalent notion to use molecular scattering data as indirect evidence for the existence of such states.
Frequency-dependent dielectric function of semiconductors with application to physisorption
The dielectric function is one of the most important quantities that describes the electrical and optical properties of solids. Accurate modeling of the frequency-dependent dielectric function has great significance in the study of the long-range van der Waals (vdW) interaction for solids and adsorption. In this work, we calculate the frequency-dependent dielectric functions of semiconductors and insulators using the $GW$ method with and without exciton effects, as well as efficient semilocal density functional theory (DFT), and compare these calculations with a model frequency-dependent diele…
Understanding, Quantifying, and Controlling the Molecular Ordering of Semi-conducting Polymers: From Novices to Experts and Amorphous to Perfect Crystals
Growth, stabilization and conversion of semi-metallic and semiconducting phases of MoTe2 monolayer by molecular-beam epitaxy
单层（ML）过渡金属二硫属化物以不同的相存在，例如六方（2 H）和畸变八面体或单斜（1 T '）相。不同的结构表现出截然不同的性质。例如，2 H MoTe 2 ML是直接带隙半导体，而1 T 'MoTe 2是半金属。有人提出，2 H和1 T 'MoTe 2之间的形成能相差很小，因此很有可能调整MoTe 2的结构，从而带来新的应用，如相变电子学。在这项工作中，我们报告的生长2 H和1 T 'MoTe 2 ML的分子束外延（MBE）。通过改变分子束外延的生长条件和退火，我们证明了外延MoTe 2结构域的可调谐性。我们目前的实验和理论证据表明，在分子束外延过程中，Te表面吸附在促进和稳定，否则亚稳1 T '-MoTe 2的重要作用。
Molecular Dynamics Simulations of Chemically Disordered Ferroelectric (Ba,Sr)TiO$_3$ with a Semi-Empirical Effective Hamiltonian
提出了一个半经验有效哈密顿量，用以描述（$_{x}$ Sr $_{1-x}$）TiO $_3$中Ba和Sr阳离子占据$A$位的无序对铁电相变的影响.在端元BaTiO $_3$和SrTiO $_3$的第一原理有效哈密顿量的参数之间取平均，我们包括一个具有经验参数的项来捕获由Ba和Sr的离子半径之间的差异引起的局部极化和应变。使用有效哈密顿量的混合空间分子动力学，我们测量了（Ba $_{x}$ Sr $_{1-x}$）TiO $_3$中$T$依赖的铁电相变，与实验结果符合得很好。我们确定有效哈密顿量中半经验参数的方法也适用于其它钙钛矿型铁电固溶体。
