title: Valley-dependent spin polarization in bulk MoS2 with broken inversion symmetry.
abstract: The valley degree of freedom of electrons is attracting growing interest as a carrier of information in various materials, including graphene, diamond and monolayer transition-metal dichalcogenides. The monolayer transition-metal dichalcogenides are semiconducting and are unique due to the coupling between the spin and valley degrees of freedom originating from the relativistic spin-orbit interaction. Here, we report the direct observation of valley-dependent out-of-plane spin polarization in an archetypal transition-metal dichalcogenide--MoS2--using spin- and angle-resolved photoemission spectroscopy. The result is in fair agreement with a first-principles theoretical prediction. This was made possible by choosing a 3R polytype crystal, which has a non-centrosymmetric structure, rather than the conventional centrosymmetric 2H form. We also confirm robust valley polarization in the 3R form by means of circularly polarized photoluminescence spectroscopy. Non-centrosymmetric transition-metal dichalcogenide crystals may provide a firm basis for the development of magnetic and electric manipulation of spin/valley degrees of freedom.
authors: 1] Quantum-Phase Electronics Centre (QPEC) and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan [2].
authors: R
authors: 0000000277029261
authors: R
authors: Suzuki
authors: 1] Quantum-Phase Electronics Centre (QPEC) and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan [2].
authors: M
authors: M
authors: Sakano
authors: Quantum-Phase Electronics Centre (QPEC) and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors: Y J
authors: YJ
authors: Zhang
authors: Quantum-Phase Electronics Centre (QPEC) and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors: R
authors: R
authors: Akashi
authors: RIKEN Centre for Emergent Matter Science, Wako 351-0198, Japan.
authors: D
authors: D
authors: Morikawa
authors: Institute for Solid State Physics, University of Tokyo, Kashiwa, 277-8581, Japan.
authors: A
authors: A
authors: Harasawa
authors: Institute for Solid State Physics, University of Tokyo, Kashiwa, 277-8581, Japan.
authors: K
authors: K
authors: Yaji
authors: Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
authors: K
authors: K
authors: Kuroda
authors: Hiroshima Synchrotron Radiation Centre, Hiroshima University, Higashi-Hiroshima 739-0046, Japan.
authors: K
authors: K
authors: Miyamoto
authors: Hiroshima Synchrotron Radiation Centre, Hiroshima University, Higashi-Hiroshima 739-0046, Japan.
authors: T
authors: T
authors: Okuda
authors: Quantum-Phase Electronics Centre (QPEC) and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
authors: K
authors: K
authors: Ishizaka
authors: 1] Quantum-Phase Electronics Centre (QPEC) and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan [2] RIKEN Centre for Emergent Matter Science, Wako 351-0198, Japan.
authors: R
authors: R
authors: Arita
authors: 1] Quantum-Phase Electronics Centre (QPEC) and Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan [2] RIKEN Centre for Emergent Matter Science, Wako 351-0198, Japan.
authors: Y
authors: Y
authors: Iwasa