标题： 一种用于第一性原理器件模拟的新方向 显示英文标题

标题： A New Direction for First-Principles Device Simulations

摘要： 半导体器件的持续微型化，以摩尔定律为代表，已达到原子尺度的极限，这要求在设备模拟中包含纳米尺度的量子力学效应，而无需经验参数。 为此，一种结合密度泛函理论（DFT）和非平衡格林函数（NEGF）理论的方法已被确立为原子尺度设备模拟的标准方法。 然而，由于基础的兰道尔或广义正则观点，DFT-NEGF方案存在一些固有的弱点。 为了克服这些挑战，多年来，我们开发了一种替代方法，即多空间约束搜索DFT（MS-DFT）形式。 这一发展的核心起点是用多空间激发观点代替兰道尔观点，或将量子输运过程映射到（微）正则系综设备模型中的能量和位置空间电子激发。 这种观点的变化导致了MS-DFT相对于其DFT-NEGF对应物的几个基本优势，例如非平衡总能量的变分确定、准费米能级分布的显式提取以及忠实模拟有限二维电极的可能性。 在本文中，我们强调MS-DFT形式的关键特征和应用。 显示英文摘要

摘要： The continued miniaturization of semiconductor devices, represented by Moore's law, has reached the atomic scale limit, requiring nanoscale quantum mechanical effects to be included in device simulations without empirical parameters. For this purpose, a method that combines density functional theory (DFT) and non-equilibrium Green's function (NEGF) theory has been established as the standard approach for atomic-scale device simulations. However, the DFT-NEGF scheme has several inherent weaknesses due to the underlying Landauer or grand canonical viewpoint. To overcome these challenges, over the years, we have developed an alternative approach, the multi-space constrained-search DFT (MS-DFT) formalism. The central starting point of this development is the replacement of the Landauer picture by the multi-space excitation viewpoint or the mapping of the quantum transport process to the energy- and position-space electron excitation within a (micro)canonical ensemble device model. This change in the viewpoint leads to several fundamental advantages of MS-DFT over its DFT-NEGF counterparts, such as the variational determination of non-equilibrium total energy, the explicit extraction of quasi-Fermi level distributions, and the possibility of faithfully modeling finite 2D electrodes. In this article, we highlight the key features and applications of the MS-DFT formalism.