title: Strain and electric-field tunable valley states in 2D van der Waals MoTe2/WTe2heterostructures.
abstract: The strain and electric-field effects on the electronic structure of MoTe2/WTe2van der Waals heterostructures are investigated by first-principles calculations. The MoTe2/WTe2heterostructures are indirect band gap semiconductors under different strains except for 2%. At a strain from  -6% to 6% under a zero electric field, the band gap is 0.56, 0.62, 0.69, 0.62, 0.46, 0.37 and 0.29 eV, respectively. Meanwhile, spin splitting at the conduction band minimum (CBM) decreases monotonically from 76-1 meV, and that at the valance band maximum (VBM) is 232, 266, 292, 307, 319, 302 and 283 meV. At an electric field from  -0.3 to 0.3 V Å-1under a 2% strain, VBM splitting decreases from 499-77 meV, but CBM splitting almost remains at 33 meV. A semiconductor-metal transition appears at an electric field of  -0.3 V Å-1. At different electric fields under a  -4% strain, CBM splitting monotonically increases from 37-154 meV, but VBM splitting is 437, 438, 378, 273, 150, 78 and 134 meV, respectively. Our results can provide a more significant basis for spintronic and valleytronic devices.
authors: Tianjin Key Laboratory of Film Electronic and Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384, People's Republic of China.
authors: Zhida
authors: Z
authors: Zheng
authors: Xiaocha
authors: X
authors: Wang
authors: Wenbo
authors: W
authors: Mi