Giant valley coherence at room temperature in 3R WS2 with broken inversion symmetry

Luojun Du, Jian Tang, Jing Liang, Mengzhou Liao, Zhiyan Jia, Qinghua Zhang, Yanchong Zhao, Rong Yang, Dongxia Shi, Lin Gu, Jianyong Xiang, Kaihui Liu, Zhipei Sun*, Guangyu Zhang

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)
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Abstract

Breaking the space-time symmetries in materials can markedly influence their electronic and optical properties. In 3R-stacked transition metal dichalcogenides, the explicitly broken inversion symmetry enables valley-contrasting Berry curvature and quantization of electronic angular momentum, providing an unprecedented platform for valleytronics. Here, we study the valley coherence of 3R WS2 large single-crystal with thicknesses ranging from monolayer to octalayer at room temperature. Our measurements demonstrate that both A and B excitons possess robust and thickness-independent valley coherence. The valley coherence of direct A (B) excitons can reach 0.742 (0.653) with excitation conditions on resonance with it. Such giant and thickness-independent valley coherence of large single-crystal 3R WS2 at room temperature would provide a firm foundation for quantum manipulation of the valley degree of freedom and practical application of valleytronics.

Original languageEnglish
Article number6494565
JournalResearch
Volume2019
DOIs
Publication statusPublished - 1 Jan 2019
MoE publication typeA1 Journal article-refereed

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