Electrical Control of Circular Photogalvanic Spin-Valley Photocurrent in a Monolayer Semiconductor

Lei Liu*, Erik J. Lenferink, Guohua Wei, Teodor K. Stanev, Nathaniel Speiser, Nathaniel P. Stern

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

In a monolayer transition metal dichalcogenide (TMDC) that lacks structural inversion symmetry, spin degeneracy is lifted by strong spin-orbit coupling, and a distinctive spin-valley locking allows for the creation of valley-locked spin-polarized carriers with a circularly polarized optical excitation. When excited carriers also have net in-plane momentum, spin-polarized photocurrents can be generated at ambient temperature without magnetic fields or materials. The behavior of these spin-polarized photocurrents in monolayer TMDC remains largely unexplored. In this work, we demonstrate the tuning of spin-valley photocurrent generated from the circularly polarized photogalvanic effect in monolayer MoS 2 , including magnitude and polarization degree, by purely electric means at room temperature. The magnitude of spin-polarized photocurrent can be modulated up to 45 times larger, and the polarization degree of the total photocurrent can be tuned significantly (here from 0.5 to 16.6%) by gate control. Combined with the atomic thickness and wafer-scale growth capabilities of monolayer TMDC, the efficient electrical tuning of spin-valley photocurrent suggests a pathway to achieve spin-logic processing by local gate architectures in monolayer opto-spintronic devices.

Original languageEnglish (US)
Pages (from-to)3334-3341
Number of pages8
JournalACS Applied Materials and Interfaces
Volume11
Issue number3
DOIs
StatePublished - Jan 23 2019

Keywords

  • circular photogalvanic effect
  • electrostatic screening
  • gate control
  • monolayer transition metal dichalcogenide
  • spin-valley photocurrent

ASJC Scopus subject areas

  • Materials Science(all)

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