Magnetic control of valley pseudospin in monolayer WSe2

被引：785

作者：

Aivazian, G. ^{[1
]}

Gong, Zhirui ^{[2
,3
]}

Jones, Aaron M. ^{[1
]}

Chu, Rui-Lin ^{[4
]}

Yan, J. ^{[5
,6
]}

Mandrus, D. G. ^{[5
,6
,7
]}

Zhang, Chuanwei ^{[4
]}

Cobden, David ^{[1
]}

Yao, Wang ^{[2
,3
]}

Xu, X. ^{[1
,8
]}

机构：

[1] Univ Washington, Dept Phys, Seattle, WA 98195 USA

[2] Univ Hong Kong, Dept Phys, Hong Kong, Hong Kong, Peoples R China

[3] Univ Hong Kong, Ctr Theoret & Computat Phys, Hong Kong, Hong Kong, Peoples R China

[4] Univ Texas Dallas, Dept Phys, Richardson, TX 75080 USA

[5] Oak Ridge Natl Lab, Mat Sci & Technol Div, Oak Ridge, TN 37831 USA

[6] Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA

[7] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA

[8] Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA

来源：

NATURE PHYSICS | 2015年 / 11卷 / 02期

关键词：

MOS2; POLARIZATION; STATES; SPIN;

D O I：

10.1038/NPHYS3201

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Local energy extrema of the bands in momentum space, or valleys, can endow electrons in solids with pseudospin in addition to real spies. In transition metal dichalcogenides this valley pseudospin, like real spin, is associated with a magnetic moment(1,6) that underlies the valley-dependent circular dichroism(6) that allows optical generation of valley polarization(7-9), intervalley quantum coherence(10) and the valley Hall effect(11). However, magnetic manipulation of valley pseudospin via this magnetic momentlz(12,13), analogous to what is possible with real spin, has not been shown before. Here we report observation of the valley Zeeman splitting and magnetic tuning of polarization and coherence of the excitonic valley pseudospin, by performing polarization-resolved magneto-photoluminescence on monolayer WSe2. Our measurements reveal both the atomic orbital and lattice contributions to the valley orbital magnetic moment; demonstrate the deviation of the band edges in the valleys from an exact massive Dirac fermion model; and reveal a striking difference between the magnetic responses of neutral and charged valley excitons that is explained by renormalization of the excitonic spectrum due to strong exchange interactions.

引用

页码：148 / 152

页数：5

共 29 条

[1] Valley-selective circular dichroism of monolayer molybdenum disulphide [J].