Anisotropic electronic, mechanical, and optical properties of monolayer WTe2
Anisotropic electronic, mechanical, and optical properties of monolayer WTe2
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DOI：
10.1063/1.4942162
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发表时间：
2016-02
影响因子：
3.2
通讯作者：
E. Torun;H. Sahin;S. Cahangirov;Á. Rubio;F. Peeters
中科院分区：
文献类型：
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作者：
E. Torun;H. Sahin;S. Cahangirov;Á. Rubio;F. Peeters
利用第一性原理计算，我们研究了单层WTe2的电子、机械和光学性质。与MoS_2、WS_2、MoSe_2、WSe_2和MoTe_2等类似的过渡金属二卤化物单层晶体不同，WTe_2(TD相)的原子结构和基态性质是各向异性的，它们在H相中结晶。我们发现，由于W原子沿化合物的一个晶格方向的二聚化引起的对称性破缺，泊松比和面内刚度是方向相关的。由于TD相的半金属行为源于这种W-W相互作用(沿a晶体方向)，沿二聚体方向的拉伸应变导致在1%应变后发生半金属到半导体的转变。通过在单激发G0W0计算的基础上求解Bethe-Salpeter方程，我们预测了TD-WTe2单分子膜的吸收光谱强烈地依赖于方向，并且可由拉伸应变来调谐。
Using first-principles calculations, we investigate the electronic, mechanical, and optical properties of monolayer WTe2. Atomic structure and ground state properties of monolayer WTe2 (Td phase) are anisotropic which are in contrast to similar monolayer crystals of transition metal dichalcogenides, such as MoS2, WS2, MoSe2, WSe2, and MoTe2, which crystallize in the H-phase. We find that the Poisson ratio and the in-plane stiffness is direction dependent due to the symmetry breaking induced by the dimerization of the W atoms along one of the lattice directions of the compound. Since the semimetallic behavior of the Td phase originates from this W-W interaction (along the a crystallographic direction), tensile strain along the dimer direction leads to a semimetal to semiconductor transition after 1% strain. By solving the Bethe-Salpeter equation on top of single shot G0W0 calculations, we predict that the absorption spectrum of Td-WTe2 monolayer is strongly direction dependent and tunable by tensile strain.