Generation, transport and detection of valley-locked spin photocurrent in WSe2–graphene–Bi2Se3 heterostructures

Soonyoung Cha, Minji Noh, Jehyun Kim, Jangyup Son, Hyemin Bae, Doeon Lee, Hoil Kim, Jekwan Lee, Ho Seung Shin, Sangwan Sim, Seunghoon Yang, Sooun Lee, Wooyoung Shim, Chul Ho Lee, Moon Ho Jo, Jun Sung Kim, Dohun Kim, Hyunyong Choi

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

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 DoF1, 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 DoF2,3, it is nontrivial to separate the spin DoF from the valley DoF since the time-reversal valley DoF is intrinsically locked with the spin DoF4. 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.

Original languageEnglish
Pages (from-to)910-914
Number of pages5
JournalNature Nanotechnology
Volume13
Issue number10
DOIs
Publication statusPublished - 2018 Oct 1

ASJC Scopus subject areas

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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    Cha, S., Noh, M., Kim, J., Son, J., Bae, H., Lee, D., Kim, H., Lee, J., Shin, H. S., Sim, S., Yang, S., Lee, S., Shim, W., Lee, C. H., Jo, M. H., Kim, J. S., Kim, D., & Choi, H. (2018). Generation, transport and detection of valley-locked spin photocurrent in WSe2–graphene–Bi2Se3 heterostructures. Nature Nanotechnology, 13(10), 910-914. https://doi.org/10.1038/s41565-018-0195-y