Anisotropic electronic, mechanical and optical properties of monolayer WTe2

Journal Of Applied Physics 119, 074307 (2016)

Anisotropic electronic, mechanical and optical properties of monolayer WTe2

E. Torun, H. Sahin, S. Cahangirov, A. Rubio,, F. M. Peeters

Using first-principles calculations we investigate the electronic, mechanical and optical proper- ties of 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 (TMDs) such as MoS2 , WS2 , MoSe2 , WSe2 , MoTe2 that 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 semicon- ductor transition. 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, after % 1 strain the gap becomes 20 meV.

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http://dx.doi.org/10.1063/1.4942162

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