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Title: Opto-valleytronic imaging of atomically thin semiconductors

Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional opto-electronics. In their monolayer form they host electrons with quantized circular motion and associated valley polarization and valley coherence as key elements of opto-valleytronic functionality. Here, we introduce two-dimensional polarimetry as means of direct imaging of the valley pseudospin degree of freedom in monolayer transition metal dichalcogenides. Using MoS 2 as a representative material with valley-selective optical transitions, we establish quantitative image analysis for polarimetric maps of extended crystals, and identify valley polarization and valley coherence as sensitive probes of crystalline disorder. Moreover, we find site-dependent thermal and non-thermal regimes of valley-polarized excitons in perpendicular magnetic fields. Finally, we demonstrate the potential of widefield polarimetry for rapid inspection of opto-valleytronic devices based on atomically thin semiconductors and heterostructures.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [2] ;  [2] ;  [3] ;  [3] ;  [1]
  1. Ludwig Maximilian Univ., Munchen (Germany)
  2. Rice Univ., Houston, TX (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-17-25599
Journal ID: ISSN 1748-3387; TRN: US1702562
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Nature Nanotechnology
Additional Journal Information:
Journal Volume: 12; Journal Issue: 4; Journal ID: ISSN 1748-3387
Publisher:
Nature Publishing Group
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; Imaging techniques; Two-dimensional materials
OSTI Identifier:
1375888