电子结构
自旋电子学
材料科学
凝聚态物理
电子能带结构
光谱学
密度泛函理论
价(化学)
化学
物理
计算化学
铁磁性
量子力学
有机化学
作者
Xin Xia,Siow Mean Loh,Jacob Viner,Natalie C. Teutsch,Abigail Graham,Viktor Kandyba,Alexei Barinov,Ana Sánchez,David C. Smith,Nicholas D. M. Hine,Neil R. Wilson
出处
期刊:JPhys materials
[IOP Publishing]
日期:2021-03-09
卷期号:4 (2): 025004-025004
被引量:7
标识
DOI:10.1088/2515-7639/abdc6e
摘要
Abstract Alloying enables engineering of the electronic structure of semiconductors for optoelectronic applications. Due to their similar lattice parameters, the two-dimensional semiconducting transition metal dichalcogenides of the MoWSeS group (MX 2 where M = Mo or W and X = S or Se) can be grown as high-quality materials with low defect concentrations. Here we investigate the atomic and electronic structure of Mo (1− x ) W x S 2 alloys using a combination of high-resolution experimental techniques and simulations. Analysis of the Mo and W atomic positions in these alloys, grown by chemical vapour transport, shows that they are randomly distributed, consistent with Monte Carlo simulations that use interaction energies determined from first-principles calculations. Electronic structure parameters are directly determined from angle resolved photoemission spectroscopy measurements. These show that the spin–orbit splitting at the valence band edge increases linearly with W content from MoS 2 to WS 2 , in agreement with linear-scaling density functional theory predictions. The spin–orbit splitting at the conduction band edge is predicted to reduce to zero at intermediate compositions. Despite this, polarisation-resolved photoluminescence spectra on monolayer Mo 0.5 W 0.5 S 2 show significant circular dichroism, indicating that spin-valley locking is retained. These results demonstrate that alloying is an important tool for controlling the electronic structure of MX 2 for spintronic and valleytronic applications.
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