Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2

Chaw Keong Yong, M. Iqbal Bakti Utama, Chin Shen Ong, Ting Cao, Emma C. Regan, Jason Horng, Yuxia Shen, Hui Cai, Kenji Watanabe, Takashi Taniguchi, Sefaattin Tongay, Hui Deng, Alex Zettl, Steven G. Louie, Feng Wang

Research output: Contribution to journalLetter

Abstract

The Berry phase of Bloch states can have profound effects on electron dynamics1–3 and lead to novel transport phenomena, such as the anomalous Hall effect and the valley Hall effect4–6. Recently, it was predicted that the Berry phase effect can also modify the exciton states in transition metal dichalcogenide monolayers, and lift the energy degeneracy of exciton states with opposite angular momentum through an effective valley-orbital coupling1,7–11. Here, we report the observation and control of the Berry phase-induced splitting of the 2p exciton states in monolayer molybdenum diselenide (MoSe2) using the intraexciton optical Stark spectroscopy. We observe the time-reversal-symmetric analogue of the orbital Zeeman effect resulting from the valley-dependent Berry phase, which leads to energy difference of +14 (−14) meV between the 2p+ and 2p exciton states in the K (K′) valley, consistent with the ordering from our ab initio GW-Bethe–Salpeter equation results. In addition, we show that the light–matter coupling between intraexciton states is remarkably strong, leading to a prominent valley-dependent Autler–Townes doublet under resonant driving. Our study opens up pathways to coherently manipulate the quantum states and excitonic excitation with infrared radiation in two-dimensional semiconductors.

Original languageEnglish (US)
JournalNature materials
DOIs
StateAccepted/In press - Jan 1 2019

Fingerprint

Excitons
valleys
Monolayers
fine structure
excitons
Molybdenum
Angular momentum
Hall effect
orbitals
Zeeman effect
Transition metals
infrared radiation
Spectroscopy
molybdenum
Semiconductor materials
Infrared radiation
angular momentum
transition metals
LDS 751
Electrons

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Yong, C. K., Utama, M. I. B., Ong, C. S., Cao, T., Regan, E. C., Horng, J., ... Wang, F. (Accepted/In press). Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2 Nature materials. https://doi.org/10.1038/s41563-019-0447-8

Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2 . / Yong, Chaw Keong; Utama, M. Iqbal Bakti; Ong, Chin Shen; Cao, Ting; Regan, Emma C.; Horng, Jason; Shen, Yuxia; Cai, Hui; Watanabe, Kenji; Taniguchi, Takashi; Tongay, Sefaattin; Deng, Hui; Zettl, Alex; Louie, Steven G.; Wang, Feng.

In: Nature materials, 01.01.2019.

Research output: Contribution to journalLetter

Yong, CK, Utama, MIB, Ong, CS, Cao, T, Regan, EC, Horng, J, Shen, Y, Cai, H, Watanabe, K, Taniguchi, T, Tongay, S, Deng, H, Zettl, A, Louie, SG & Wang, F 2019, 'Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2 ', Nature materials. https://doi.org/10.1038/s41563-019-0447-8
Yong, Chaw Keong ; Utama, M. Iqbal Bakti ; Ong, Chin Shen ; Cao, Ting ; Regan, Emma C. ; Horng, Jason ; Shen, Yuxia ; Cai, Hui ; Watanabe, Kenji ; Taniguchi, Takashi ; Tongay, Sefaattin ; Deng, Hui ; Zettl, Alex ; Louie, Steven G. ; Wang, Feng. / Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2 In: Nature materials. 2019.
@article{dd20d8d12ce645ee8a25eae8f0ada179,
title = "Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2",
abstract = "The Berry phase of Bloch states can have profound effects on electron dynamics1–3 and lead to novel transport phenomena, such as the anomalous Hall effect and the valley Hall effect4–6. Recently, it was predicted that the Berry phase effect can also modify the exciton states in transition metal dichalcogenide monolayers, and lift the energy degeneracy of exciton states with opposite angular momentum through an effective valley-orbital coupling1,7–11. Here, we report the observation and control of the Berry phase-induced splitting of the 2p exciton states in monolayer molybdenum diselenide (MoSe2) using the intraexciton optical Stark spectroscopy. We observe the time-reversal-symmetric analogue of the orbital Zeeman effect resulting from the valley-dependent Berry phase, which leads to energy difference of +14 (−14) meV between the 2p+ and 2p− exciton states in the K (K′) valley, consistent with the ordering from our ab initio GW-Bethe–Salpeter equation results. In addition, we show that the light–matter coupling between intraexciton states is remarkably strong, leading to a prominent valley-dependent Autler–Townes doublet under resonant driving. Our study opens up pathways to coherently manipulate the quantum states and excitonic excitation with infrared radiation in two-dimensional semiconductors.",
author = "Yong, {Chaw Keong} and Utama, {M. Iqbal Bakti} and Ong, {Chin Shen} and Ting Cao and Regan, {Emma C.} and Jason Horng and Yuxia Shen and Hui Cai and Kenji Watanabe and Takashi Taniguchi and Sefaattin Tongay and Hui Deng and Alex Zettl and Louie, {Steven G.} and Feng Wang",
year = "2019",
month = "1",
day = "1",
doi = "10.1038/s41563-019-0447-8",
language = "English (US)",
journal = "Nature Materials",
issn = "1476-1122",
publisher = "Nature Publishing Group",

}

TY - JOUR

T1 - Valley-dependent exciton fine structure and Autler–Townes doublets from Berry phases in monolayer MoSe2

AU - Yong, Chaw Keong

AU - Utama, M. Iqbal Bakti

AU - Ong, Chin Shen

AU - Cao, Ting

AU - Regan, Emma C.

AU - Horng, Jason

AU - Shen, Yuxia

AU - Cai, Hui

AU - Watanabe, Kenji

AU - Taniguchi, Takashi

AU - Tongay, Sefaattin

AU - Deng, Hui

AU - Zettl, Alex

AU - Louie, Steven G.

AU - Wang, Feng

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The Berry phase of Bloch states can have profound effects on electron dynamics1–3 and lead to novel transport phenomena, such as the anomalous Hall effect and the valley Hall effect4–6. Recently, it was predicted that the Berry phase effect can also modify the exciton states in transition metal dichalcogenide monolayers, and lift the energy degeneracy of exciton states with opposite angular momentum through an effective valley-orbital coupling1,7–11. Here, we report the observation and control of the Berry phase-induced splitting of the 2p exciton states in monolayer molybdenum diselenide (MoSe2) using the intraexciton optical Stark spectroscopy. We observe the time-reversal-symmetric analogue of the orbital Zeeman effect resulting from the valley-dependent Berry phase, which leads to energy difference of +14 (−14) meV between the 2p+ and 2p− exciton states in the K (K′) valley, consistent with the ordering from our ab initio GW-Bethe–Salpeter equation results. In addition, we show that the light–matter coupling between intraexciton states is remarkably strong, leading to a prominent valley-dependent Autler–Townes doublet under resonant driving. Our study opens up pathways to coherently manipulate the quantum states and excitonic excitation with infrared radiation in two-dimensional semiconductors.

AB - The Berry phase of Bloch states can have profound effects on electron dynamics1–3 and lead to novel transport phenomena, such as the anomalous Hall effect and the valley Hall effect4–6. Recently, it was predicted that the Berry phase effect can also modify the exciton states in transition metal dichalcogenide monolayers, and lift the energy degeneracy of exciton states with opposite angular momentum through an effective valley-orbital coupling1,7–11. Here, we report the observation and control of the Berry phase-induced splitting of the 2p exciton states in monolayer molybdenum diselenide (MoSe2) using the intraexciton optical Stark spectroscopy. We observe the time-reversal-symmetric analogue of the orbital Zeeman effect resulting from the valley-dependent Berry phase, which leads to energy difference of +14 (−14) meV between the 2p+ and 2p− exciton states in the K (K′) valley, consistent with the ordering from our ab initio GW-Bethe–Salpeter equation results. In addition, we show that the light–matter coupling between intraexciton states is remarkably strong, leading to a prominent valley-dependent Autler–Townes doublet under resonant driving. Our study opens up pathways to coherently manipulate the quantum states and excitonic excitation with infrared radiation in two-dimensional semiconductors.

UR - http://www.scopus.com/inward/record.url?scp=85070278512&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85070278512&partnerID=8YFLogxK

U2 - 10.1038/s41563-019-0447-8

DO - 10.1038/s41563-019-0447-8

M3 - Letter

JO - Nature Materials

JF - Nature Materials

SN - 1476-1122

ER -