Spin-layer- And spin-valley-locking due to symmetry in differently-stacked tungsten disulfide bilayers

Lorenz M. Schneider, Jan Kuhnert, Simon Schmitt, Ulrich Huttner, Lars Meckbach, Tineke Stroucken, Stephan W. Koch, Wolfram Heimbrodt, Shichen Fu, Xiaotian Wang, Kyungnam Kang, Eui Hyeok Yang, Arash Rahimi-Iman

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The coupling of the spin and valley degrees of freedom and valley-selective optical selection rules in transition-metal dichalcogenides (TMDCs) monolayers (ML) has been a major research topic in recent years [1]. In contrast, valleytronic properties of TMDC bilayers have not been in the focus so much by now. In our contribution, we study the effect of the relative layer alignment in TMDC homo-bilayer samples on their polarization-dependent optical properties. To this end, CVD-grown WS2 bilayer samples have been prepared that during synthesis favour either the inversion symmetric AA' or AB stacking without inversion symmetry. For the optical studies, the bilayer samples were transferred either onto a bare SiO2 (cf. fig. 1 a,b) or a few-layer h-BN buffer (fig. 1 c,d). To verify the difference in symmetry for these bilayer configurations, second-harmonic-generation (SHG) raster-scans have been performed (cf. fig. 1 e-h), confirming inversion symmetry for the AA' configuration. Subsequently, a detailed analysis of reflection contrast and photoluminescence (PL) spectra under different polarization conditions has been performed.

Original languageEnglish
Title of host publicationEuropean Quantum Electronics Conference, EQEC_2019
StatePublished - 2019
EventEuropean Quantum Electronics Conference, EQEC_2019 - Munich, United Kingdom
Duration: 23 Jun 201927 Jun 2019

Publication series

NameOptics InfoBase Conference Papers
VolumePart F143-EQEC 2019
ISSN (Electronic)2162-2701

Conference

ConferenceEuropean Quantum Electronics Conference, EQEC_2019
Country/TerritoryUnited Kingdom
CityMunich
Period23/06/1927/06/19

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