Resolution of the exponent puzzle for the Anderson transition in doped semiconductors
Resolution of the exponent puzzle for the Anderson transition in doped semiconductors
复制标题
DOI：
10.1103/physrevb.99.081201
复制
发表时间：
2019-02-06
影响因子：
3.7
通讯作者：
Romer, Rudolf A.
中科院分区：
文献类型：
--
作者：
Carnio, Edoardo G.;Hine, Nicholas D. M.;Romer, Rudolf A.
安德森金属-绝缘体转变（MIT）是我们理解无序材料的量子力学性质的核心。尽管在理论和实验上做了大量的努力，但对于描述相变普适性的临界指数v的取值仍然没有达成一致，即所谓的“指数之谜”。“在这个快速通信中，超越了标准的安德森模型，我们采用从头算方法来研究掺杂半导体的现实模型中的MIT。我们使用线性标度密度泛函理论模拟原型的硫掺杂硅（Si：S）。从这些，我们建立更大的紧束缚模型接近临界浓度的MIT。当掺杂剂浓度增加时，杂质带形成并最终离域。我们通过多重分形有限尺寸标度表征MIT，获得相图和V的估计。我们的研究结果表明，长期存在的指数之谜的解释，我们链接到导电带和杂质带的杂交。
The Anderson metal-insulator transition (MIT) is central to our understanding of the quantum mechanical nature of disordered materials. Despite extensive efforts by theory and experiment, there is still no agreement on the value of the critical exponent v describing the universality of the transition-the so-called "exponent puzzle." In this Rapid Communication, going beyond the standard Anderson model, we employ ab initio methods to study the MIT in a realistic model of a doped semiconductor. We use linear-scaling density functional theory to simulate prototypes of sulfur-doped silicon (Si:S). From these we build larger tight-binding models close to the critical concentration of the MIT. When the dopant concentration is increased, an impurity band forms and eventually delocalizes. We characterize the MIT via multifractal finite-size scaling, obtaining the phase diagram and estimates of v. Our results suggest an explanation of the long-standing exponent puzzle, which we link to the hybridization of conduction and impurity bands.