Direct measurement of exciton valley coherence in monolayer WSe2

Handle URI:
http://hdl.handle.net/10754/622388
Title:
Direct measurement of exciton valley coherence in monolayer WSe2
Authors:
Hao, Kai; Moody, Galan; Wu, Fengcheng; Dass, Chandriker Kavir; Xu, Lixiang; Chen, Chang Hsiao; Sun, Liuyang; Li, Ming-yang; Li, Lain-Jong ( 0000-0002-4059-7783 ) ; MacDonald, Allan H.; Li, Xiaoqin
Abstract:
<p>In crystals, energy band extrema in momentum space can be identified by a valley index. The internal quantum degree of freedom associated with valley pseudospin indices can act as a useful information carrier, analogous to electronic charge or spin. Interest in valleytronics has been revived in recent years following the discovery of atomically thin materials such as graphene and transition metal dichalcogenides. However, the valley coherence time—a crucial quantity for valley pseudospin manipulation—is difficult to directly probe. In this work, we use two-dimensional coherent spectroscopy to resonantly generate and detect valley coherence of excitons (Coulomb-bound electron–hole pairs) in monolayer WSe<sub>2</sub> (refs <span></span>,<span></span>). The imposed valley coherence persists for approximately one hundred femtoseconds. We propose that the electron–hole exchange interaction provides an important decoherence mechanism in addition to exciton population recombination. This work provides critical insight into the requirements and strategies for optical manipulation of the valley pseudospin for future valleytronics applications.</p>
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Hao K, Moody G, Wu F, Dass CK, Xu L, et al. (2016) Direct measurement of exciton valley coherence in monolayer WSe2. Nature Physics 12: 677–682. Available: http://dx.doi.org/10.1038/nphys3674.
Publisher:
Springer Nature
Journal:
Nature Physics
Issue Date:
29-Feb-2016
DOI:
10.1038/nphys3674
Type:
Article
ISSN:
1745-2473; 1745-2481
Sponsors:
The theoretical and experimental collaboration is made possible by SHINES, an Energy Frontier Research Center funded by the US Derailment of Energy (DoE), Office of Science, Basic Energy-Science (BES) under award # DE-SC0012070. K.H., F.W., L.X., X.L. and A.H.M. have all received support from SHINES. Optical spectroscopy studies performed by K.H., C.K.D., L.S. and X.L. have been partially supported by NSF DMR-1306878 and Welch Foundation F-1662. A.H.M. also acknowledges support from Welch Foundation F-1473. L.J.L. is grateful for support from KAUST Saudi Arabia, Academia Sinica Taiwan, and AOARD FA23861510001 USA. C.-H.C. is grateful for support from the Ministry of Science and Technology Taiwan (MOST 104-2218-E-035-010 and 104-2628-E-035-002-MY3).
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorHao, Kaien
dc.contributor.authorMoody, Galanen
dc.contributor.authorWu, Fengchengen
dc.contributor.authorDass, Chandriker Kaviren
dc.contributor.authorXu, Lixiangen
dc.contributor.authorChen, Chang Hsiaoen
dc.contributor.authorSun, Liuyangen
dc.contributor.authorLi, Ming-yangen
dc.contributor.authorLi, Lain-Jongen
dc.contributor.authorMacDonald, Allan H.en
dc.contributor.authorLi, Xiaoqinen
dc.date.accessioned2017-01-02T09:28:28Z-
dc.date.available2017-01-02T09:28:28Z-
dc.date.issued2016-02-29en
dc.identifier.citationHao K, Moody G, Wu F, Dass CK, Xu L, et al. (2016) Direct measurement of exciton valley coherence in monolayer WSe2. Nature Physics 12: 677–682. Available: http://dx.doi.org/10.1038/nphys3674.en
dc.identifier.issn1745-2473en
dc.identifier.issn1745-2481en
dc.identifier.doi10.1038/nphys3674en
dc.identifier.urihttp://hdl.handle.net/10754/622388-
dc.description.abstract<p>In crystals, energy band extrema in momentum space can be identified by a valley index. The internal quantum degree of freedom associated with valley pseudospin indices can act as a useful information carrier, analogous to electronic charge or spin. Interest in valleytronics has been revived in recent years following the discovery of atomically thin materials such as graphene and transition metal dichalcogenides. However, the valley coherence time—a crucial quantity for valley pseudospin manipulation—is difficult to directly probe. In this work, we use two-dimensional coherent spectroscopy to resonantly generate and detect valley coherence of excitons (Coulomb-bound electron–hole pairs) in monolayer WSe<sub>2</sub> (refs <span></span>,<span></span>). The imposed valley coherence persists for approximately one hundred femtoseconds. We propose that the electron–hole exchange interaction provides an important decoherence mechanism in addition to exciton population recombination. This work provides critical insight into the requirements and strategies for optical manipulation of the valley pseudospin for future valleytronics applications.</p>en
dc.description.sponsorshipThe theoretical and experimental collaboration is made possible by SHINES, an Energy Frontier Research Center funded by the US Derailment of Energy (DoE), Office of Science, Basic Energy-Science (BES) under award # DE-SC0012070. K.H., F.W., L.X., X.L. and A.H.M. have all received support from SHINES. Optical spectroscopy studies performed by K.H., C.K.D., L.S. and X.L. have been partially supported by NSF DMR-1306878 and Welch Foundation F-1662. A.H.M. also acknowledges support from Welch Foundation F-1473. L.J.L. is grateful for support from KAUST Saudi Arabia, Academia Sinica Taiwan, and AOARD FA23861510001 USA. C.-H.C. is grateful for support from the Ministry of Science and Technology Taiwan (MOST 104-2218-E-035-010 and 104-2628-E-035-002-MY3).en
dc.publisherSpringer Natureen
dc.subjectElectronic properties and materialsen
dc.subjectTwo-dimensional materialsen
dc.subjectQuantum mechanicsen
dc.subjectNear-infrared spectroscopyen
dc.titleDirect measurement of exciton valley coherence in monolayer WSe2en
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalNature Physicsen
dc.contributor.institutionDepartment of Physics, Center for Complex Quantum Systems, University of Texas at Austin, Austin, TX, 78712, United Statesen
dc.contributor.institutionNational Institute of Standards and Technology, Boulder, CO, 80305, United Statesen
dc.contributor.institutionDepartment of Automatic Control Engineering, Feng Chia University, Taichung, 40724, Taiwanen
kaust.authorLi, Ming-yangen
kaust.authorLi, Lain-Jongen
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