title: Electrical generation and control of the valley carriers in a monolayer transition metal dichalcogenide.
abstract: Electrically controlling the flow of charge carriers is the foundation of modern electronics. By accessing the extra spin degree of freedom (DOF) in electronics, spintronics allows for information processes such as magnetoresistive random-access memory. Recently, atomic membranes of transition metal dichalcogenides (TMDCs) were found to support unequal and distinguishable carrier distribution in different crystal momentum valleys. This valley polarization of carriers enables a new DOF for information processing. A variety of valleytronic devices such as valley filters and valves have been proposed, and optical valley excitation has been observed. However, to realize its potential in electronics it is necessary to electrically control the valley DOF, which has so far remained a significant challenge. Here, we experimentally demonstrate the electrical generation and control of valley polarization. This is achieved through spin injection via a diluted ferromagnetic semiconductor and measured through the helicity of the electroluminescence due to the spin-valley locking in TMDC monolayers. We also report a new scheme of electronic devices that combine both the spin and valley DOFs. Such direct electrical generation and control of valley carriers opens up new dimensions in utilizing both the spin and valley DOFs for next-generation electronics and computing.
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ye
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 10083, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: Wang
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Ziliang
authors.initials: Z
authors.lastname: Ye
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Hanyu
authors.initials: H
authors.lastname: Zhu
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Mervin
authors.initials: M
authors.lastname: Zhao
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 10083, China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Mechanical Engineering and Materials Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, USA.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Yin
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, 3112 Etcheverry Hall, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.|Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang