Valley Phenomena in the Candidate Phase Change Material Wse2(1-X)Te2x
Abstract
Alloyed transition metal dichalcogenides provide an opportunity for coupling band engineering with valleytronic phenomena in an atomically-thin platform. However, valley properties in alloys remain largely unexplored. We investigate the valley degree of freedom in monolayer alloys of the phase change candidate material WSe2(1-x)Te2x. Low temperature Raman measurements track the alloy-induced transition from the semiconducting 1H phase of WSe2 to the semimetallic 1Td phase of WTe2. We correlate these observations with density functional theory calculations and identify new Raman modes from W-Te vibrations in the 1H-phase alloy. Photoluminescence measurements show ultra-low energy emission features that highlight alloy disorder arising from the large W-Te bond lengths. Interestingly, valley polarization and coherence in alloys survive at high Te compositions and are more robust against temperature than in WSe2. These findings illustrate the persistence of valley properties in alloys with highly dissimilar parent compounds and suggest band engineering can be utilized for valleytronic devices.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 15, 2020
- Accession Number
- AD1096089
Entities
People
- Albert V Davydov
- Joshua Young
- Patrick M Vora
- Sean M Oliver
- Sergiy Krylyuk
- Thomas L. Reinecke
Organizations
- United States Naval Research Laboratory