• 文献标题:   Generation, transport and detection of valley-locked spin photocurrent in WSe2-graphene-Bi2Se3 heterostructures
  • 文献类型:   Article
  • 作  者:   CHA S, NOH M, KIM J, SON J, BAE H, LEE D, KIM H, LEE J, SHIN HS, SIM S, YANG S, LEE S, SHIM W, LEE CH, JO MH, KIM JS, KIM D, CHOI H
  • 作者关键词:  
  • 出版物名称:   NATURE NANOTECHNOLOGY
  • ISSN:   1748-3387 EI 1748-3395
  • 通讯作者地址:   Yonsei Univ
  • 被引频次:   5
  • DOI:   10.1038/s41565-018-0195-y
  • 出版年:   2018

▎ 摘  要

Quantum optoelectronic devices capable of isolating a target degree of freedom (DoF) from other DoFs have allowed for new applications in modern information technology. Many works on solid-state spintronics have focused on methods to disentangle the spin DoF from the charge DoF(1), yet many related issues remain unresolved. Although the recent advent of atomically thin transition metal dichalcogenides (TMDs) has enabled the use of valley pseudospin as an alternative DoF(2,3), it is nontrivial to separate the spin DoF from the valley DoF since the time-reversal valley DoF is intrinsically locked with the spin DoF(4). Here, we demonstrate lateral TMD-graphene-topological insulator hetero-devices with the possibility of such a DoF-selective measurement. We generate the valley-locked spin DoF via a circular photogalvanic effect in an electric-double-layer WSe2 transistor. The valley-locked spin photocarriers then diffuse in a submicrometre-long graphene layer, and the spin DoF is measured separately in the topological insulator via non-local electrical detection using the characteristic spin-momentum locking. Operating at room temperature, our integrated devices exhibit a non-local spin polarization degree of higher than 0.5, providing the potential for coupled opto-spin-valleytronic applications that independently exploit the valley and spin DoFs.