Park, Jaehong Yeu, In Won Han, Gyuseung Jang, Chaun Kwak, Joon Young Hwang, Cheol Seong Choi, Jung-Hae 2024-01-19T19:31:44Z 2024-01-19T19:31:44Z 2021-09-02 2019-08-07 0953-8984 https://pubs.kist.re.kr/handle/201004/119689 Electrons in two-dimensional layered crystals gain a discrete positional degree of freedom over layers. We propose the two-dimensional transition metal dichalcogenide homostructure with polar symmetry as a prototypical platform where the degrees of freedom for the layers and valleys can be independently controlled through an optical method. In 3R MoS2, a model system, the presence of the spontaneous polarization and built-in electric field along the stacking axis is theoretically proven by the density functional theory. The K valley states under the electric field exhibit Wannier-Stark type localization with atomic-scale confinement driven by double group symmetry. The simple interlayer-dynamics-selection rule of the valley carriers in 3R homostructure enables a binary operation, upward or downward motion, using visible and infrared light sources. Together with the valley-index, a 2 circle times 2 states/cell device using a dual-frequency polarized light source is suggested. English IOP PUBLISHING LTD TOTAL-ENERGY CALCULATIONS CHARGE-TRANSFER SPIN POLARIZATION CRYSTALS EXCITONS Optical control of the layer degree of freedom through Wannier-Stark states in polar 3R MoS2 Article 10.1088/1361-648X/ab1d0f 1 JOURNAL OF PHYSICS-CONDENSED MATTER, v.31, no.31 JOURNAL OF PHYSICS-CONDENSED MATTER 31 31 scie scopus 000468946400001 2-s2.0-85067218160 Physics, Condensed Matter Physics Article TOTAL-ENERGY CALCULATIONS CHARGE-TRANSFER SPIN POLARIZATION CRYSTALS EXCITONS polar symmetry 3R MoS2 layer-index optical selection rule transition metal dichalcogenide