Imaging spin dynamics in monolayer WS2 by time-resolved Kerr rotation microscopy

被引：57

作者：

McCormick, Elizabeth J. ^{[1
]}

Newburger, Michael J. ^{[1
]}

Luo, Yunqiu Kelly ^{[1
]}

McCreary, Kathleen M. ^{[2
]}

Singh, Simranjeet ^{[1
]}

Martin, Iwan B. ^{[1
]}

Cichewicz, Edward J., Jr. ^{[1
]}

Jonker, Berend T. ^{[2
]}

Kawakami, Roland K. ^{[1
]}

机构：

[1] Ohio State Univ, Dept Phys, 174 W 18th Ave, Columbus, OH 43210 USA

[2] Naval Res Lab, Washington, DC 20375 USA

来源：

2D MATERIALS | 2018年 / 5卷 / 01期

关键词：

transition metal dichalcogenides; spin Ironies; valleytronics; Kerr rotation; VALLEY POLARIZATION; RELAXATION; ELECTRONS; MOS2; PHOTOLUMINESCENCE; COHERENCE;

D O I：

10.1088/2053-1583/aa98ae

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Monolayer transition metal dichalcogenides (TMD) have immense potential for future spintronic and valleytronic applications due to their 2D nature and long spin/valley lifetimes. We investigate the origin of these long-lived states in n-type WS2 using time-resolved Kerr rotation microscopy and photoluminescence microscopy with similar to 1 mu m spatial resolution. Comparing the spatial dependence of the Kerr rotation signal and the photoluminescence reveals a correlation with neutral exciton emission, which is likely due to the transfer of angular momentum to resident conduction electrons with long spin/valley lifetimes. In addition, we observe an unexpected anticorrelation between the Kerr rotation and trion emission, which provides evidence for the presence of long-lived spin/valley-polarized dark trions. We also find that the spin/valley polarization in WS2 is robust to magnetic fields up to 700 mT, indicative of spins and valleys that are stabilized with strong spin-orbit fields.

引用

页数：10

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