Exact muffin tin orbital based first-principles method for electronic-structure and electron-transport simulation of device materials

作者：Qingyun Zhang, Jiawei Yan, Yu Zhang, Youqi Ke · 发表于：Physical review. B./Physical review. B · 年份：2019 · DOI：10.1103/physrevb.100.075134 · 被引用次数：23 · 研究领域：Magnetic properties of thin films、Quantum and electron transport phenomena、Surface and Thin Film Phenomena

The exact muffin tin orbital (EMTO) method features high efficiency and accuracy for first-principles simulations with density functional theory. In this paper we report our implementation of the EMTO method for electronic-structure and quantum transport simulation of device materials. We consider a device-material structure with a central device region in contact with different semi-infinite electrodes. Based on the Green's function method, the infinite device, nonperiodic in transport direction, is transformed into a calculable finite material system by treating the semi-infinite electrodes with electrode self-energies, and the Green's function of the device region is calculated with an efficient recursive technique. In the present implementation we adopt the spherical cell approximation to treat the electrostatics, and we solve the electrostatic potential of the finite device region by enforcing the boundary conditions to the known potential of electrode materials. The coherent potential approximation is incorporated for treating the atomic disorders inevitable in realistic materials, and the effects of multiple disorder scattering on electron transport are accounted for by vertex correction for simulating disordered electronic devices. To demonstrate the capability of the present implementation, we calculate the monolayer two-dimensional material ${\mathrm{MoS}}_{2}$ and black phosphorus, and study the spin-dependent tunneling in the Fe/MgO/Fe magnetic tunneling junction....