Superior Valley Polarization and Coherence of 2s Excitons in Monolayer WSe2

被引：38

作者：

Chen, Shao-Yu ^{[1
]}

Goldstein, Thomas ^{[1
]}

Tong, Jiayue ^{[1
]}

Taniguchi, Takashi ^{[2
]}

Watanabe, Kenji ^{[2
]}

Yan, Jun ^{[1
]}

机构：

[1] Univ Massachusetts, Dept Phys, Amherst, MA 01003 USA

[2] Natl Inst Mat Sci, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan

来源：

PHYSICAL REVIEW LETTERS | 2018年 / 120卷 / 04期

基金：

美国国家科学基金会; 日本学术振兴会;

关键词：

MOS2; SCATTERING; WS2; LUMINESCENCE; DYNAMICS; STATES; MODES;

D O I：

10.1103/PhysRevLett.120.046402

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We report the experimental observation of 2s exciton radiative emission from monolayer tungsten diselenide, enabled by hexagonal boron nitride protected high-quality samples. The 2s luminescence is highly robust and persists up to 150 K, offering a new quantum entity for manipulating the valley degree of freedom. Remarkably, the 2s exciton displays superior valley polarization and coherence than 1s under similar experimental conditions. This observation provides evidence that the Coulomb-exchange-interaction-driven valley-depolarization process, the Maialle-Silva-Sham mechanism, plays an important role in valley excitons of monolayer transition metal dichalcogenides.

引用

页数：6

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