Intrinsic spin-valley locking for conducting electrons in metal-semiconductor-metal lateral heterostructures of 1H -transition-metal dichalcogenides

Abstract

Lateral heterostructures of atomic layered materials alter the electronic properties of pristine crystals and provide a possibility to produce useful monolayer materials. We reveal that metal-semiconductor-metal lateral heterojunctions of $1H$-transition-metal dichalcogenides intrinsically possess conducting channels of electrons with spin-valley locking without any extrinsic fabrication breaking the crystal symmetry, e.g., gate electrodes. We theoretically investigate the electronic structure and transport properties of lateral heterojunctions and show that the heterostructure produces conducting channels through the $K$ and ${K}^{\ensuremath{'}}$ valleys in the semiconducting transition-metal dichalcogenides and restricts the spin of the conducting electrons in each valley due to the valley-dependent charge transfer effect. Moreover, the theoretical investigation shows that the heterojunction of ${\mathrm{WSe}}_{2}$ realizes a high transmission probability for valley-spin locked electrons even in a long semiconducting region. The heterojunction also provides a useful electronic transport property, a steplike I-V characteristic.