Electrically switchable Berry curvature dipole in the monolayer topological insulator WTe 2

Su Yang Xu, Qiong Ma, Huitao Shen, Valla Fatemi, Sanfeng Wu, Tay-Rong Chang, Guoqing Chang, Andrés M.Mier Valdivia, Ching Kit Chan, Quinn D. Gibson, Jiadong Zhou, Zheng Liu, Kenji Watanabe, Takashi Taniguchi, Hsin Lin, Robert J. Cava, Liang Fu, Nuh Gedik, Pablo Jarillo-Herrero

Research output: Contribution to journalLetter

32 Citations (Scopus)

Abstract

Recent experimental evidence for the quantum spin Hall (QSH) state in monolayer WTe 2 has linked the fields of two-dimensional materials and topological physics 1–7 . This two-dimensional topological crystal also displays unconventional spin–torque 8 and gate-tunable superconductivity 7 . Whereas the realization of the QSH has demonstrated the nontrivial topology of the electron wavefunctions of monolayer WTe 2 , the geometrical properties of the wavefunction, such as the Berry curvature 9 , remain unstudied. Here we utilize mid-infrared optoelectronic microscopy to investigate the Berry curvature in monolayer WTe 2 . By optically exciting electrons across the inverted QSH gap, we observe an in-plane circular photogalvanic current even under normal incidence. The application of an out-of-plane displacement field allows further control of the direction and magnitude of the photocurrent. The observed photocurrent reveals a Berry curvature dipole that arises from the nontrivial wavefunctions near the inverted gap edge. The Berry curvature dipole and strong electric field effect are enabled by the inverted band structure and tilted crystal lattice of monolayer WTe 2 . Such an electrically switchable Berry curvature dipole may facilitate the observation of a wide range of quantum geometrical phenomena such as the quantum nonlinear Hall 10,11 , orbital-Edelstein 12 and chiral polaritonic effects 13,14 .

Original languageEnglish
Pages (from-to)900-906
Number of pages7
JournalNature Physics
Volume14
Issue number9
DOIs
Publication statusPublished - 2018 Sep 1

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curvature
insulators
dipoles
photocurrents
crystal lattices
far fields
electrons
superconductivity
topology
incidence
microscopy
orbitals
physics
electric fields
crystals

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Xu, Su Yang ; Ma, Qiong ; Shen, Huitao ; Fatemi, Valla ; Wu, Sanfeng ; Chang, Tay-Rong ; Chang, Guoqing ; Valdivia, Andrés M.Mier ; Chan, Ching Kit ; Gibson, Quinn D. ; Zhou, Jiadong ; Liu, Zheng ; Watanabe, Kenji ; Taniguchi, Takashi ; Lin, Hsin ; Cava, Robert J. ; Fu, Liang ; Gedik, Nuh ; Jarillo-Herrero, Pablo. / Electrically switchable Berry curvature dipole in the monolayer topological insulator WTe 2 In: Nature Physics. 2018 ; Vol. 14, No. 9. pp. 900-906.
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title = "Electrically switchable Berry curvature dipole in the monolayer topological insulator WTe 2",
abstract = "Recent experimental evidence for the quantum spin Hall (QSH) state in monolayer WTe 2 has linked the fields of two-dimensional materials and topological physics 1–7 . This two-dimensional topological crystal also displays unconventional spin–torque 8 and gate-tunable superconductivity 7 . Whereas the realization of the QSH has demonstrated the nontrivial topology of the electron wavefunctions of monolayer WTe 2 , the geometrical properties of the wavefunction, such as the Berry curvature 9 , remain unstudied. Here we utilize mid-infrared optoelectronic microscopy to investigate the Berry curvature in monolayer WTe 2 . By optically exciting electrons across the inverted QSH gap, we observe an in-plane circular photogalvanic current even under normal incidence. The application of an out-of-plane displacement field allows further control of the direction and magnitude of the photocurrent. The observed photocurrent reveals a Berry curvature dipole that arises from the nontrivial wavefunctions near the inverted gap edge. The Berry curvature dipole and strong electric field effect are enabled by the inverted band structure and tilted crystal lattice of monolayer WTe 2 . Such an electrically switchable Berry curvature dipole may facilitate the observation of a wide range of quantum geometrical phenomena such as the quantum nonlinear Hall 10,11 , orbital-Edelstein 12 and chiral polaritonic effects 13,14 .",
author = "Xu, {Su Yang} and Qiong Ma and Huitao Shen and Valla Fatemi and Sanfeng Wu and Tay-Rong Chang and Guoqing Chang and Valdivia, {Andr{\'e}s M.Mier} and Chan, {Ching Kit} and Gibson, {Quinn D.} and Jiadong Zhou and Zheng Liu and Kenji Watanabe and Takashi Taniguchi and Hsin Lin and Cava, {Robert J.} and Liang Fu and Nuh Gedik and Pablo Jarillo-Herrero",
year = "2018",
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day = "1",
doi = "10.1038/s41567-018-0189-6",
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Xu, SY, Ma, Q, Shen, H, Fatemi, V, Wu, S, Chang, T-R, Chang, G, Valdivia, AMM, Chan, CK, Gibson, QD, Zhou, J, Liu, Z, Watanabe, K, Taniguchi, T, Lin, H, Cava, RJ, Fu, L, Gedik, N & Jarillo-Herrero, P 2018, ' Electrically switchable Berry curvature dipole in the monolayer topological insulator WTe 2 ', Nature Physics, vol. 14, no. 9, pp. 900-906. https://doi.org/10.1038/s41567-018-0189-6

Electrically switchable Berry curvature dipole in the monolayer topological insulator WTe 2 . / Xu, Su Yang; Ma, Qiong; Shen, Huitao; Fatemi, Valla; Wu, Sanfeng; Chang, Tay-Rong; Chang, Guoqing; Valdivia, Andrés M.Mier; Chan, Ching Kit; Gibson, Quinn D.; Zhou, Jiadong; Liu, Zheng; Watanabe, Kenji; Taniguchi, Takashi; Lin, Hsin; Cava, Robert J.; Fu, Liang; Gedik, Nuh; Jarillo-Herrero, Pablo.

In: Nature Physics, Vol. 14, No. 9, 01.09.2018, p. 900-906.

Research output: Contribution to journalLetter

TY - JOUR

T1 - Electrically switchable Berry curvature dipole in the monolayer topological insulator WTe 2

AU - Xu, Su Yang

AU - Ma, Qiong

AU - Shen, Huitao

AU - Fatemi, Valla

AU - Wu, Sanfeng

AU - Chang, Tay-Rong

AU - Chang, Guoqing

AU - Valdivia, Andrés M.Mier

AU - Chan, Ching Kit

AU - Gibson, Quinn D.

AU - Zhou, Jiadong

AU - Liu, Zheng

AU - Watanabe, Kenji

AU - Taniguchi, Takashi

AU - Lin, Hsin

AU - Cava, Robert J.

AU - Fu, Liang

AU - Gedik, Nuh

AU - Jarillo-Herrero, Pablo

PY - 2018/9/1

Y1 - 2018/9/1

N2 - Recent experimental evidence for the quantum spin Hall (QSH) state in monolayer WTe 2 has linked the fields of two-dimensional materials and topological physics 1–7 . This two-dimensional topological crystal also displays unconventional spin–torque 8 and gate-tunable superconductivity 7 . Whereas the realization of the QSH has demonstrated the nontrivial topology of the electron wavefunctions of monolayer WTe 2 , the geometrical properties of the wavefunction, such as the Berry curvature 9 , remain unstudied. Here we utilize mid-infrared optoelectronic microscopy to investigate the Berry curvature in monolayer WTe 2 . By optically exciting electrons across the inverted QSH gap, we observe an in-plane circular photogalvanic current even under normal incidence. The application of an out-of-plane displacement field allows further control of the direction and magnitude of the photocurrent. The observed photocurrent reveals a Berry curvature dipole that arises from the nontrivial wavefunctions near the inverted gap edge. The Berry curvature dipole and strong electric field effect are enabled by the inverted band structure and tilted crystal lattice of monolayer WTe 2 . Such an electrically switchable Berry curvature dipole may facilitate the observation of a wide range of quantum geometrical phenomena such as the quantum nonlinear Hall 10,11 , orbital-Edelstein 12 and chiral polaritonic effects 13,14 .

AB - Recent experimental evidence for the quantum spin Hall (QSH) state in monolayer WTe 2 has linked the fields of two-dimensional materials and topological physics 1–7 . This two-dimensional topological crystal also displays unconventional spin–torque 8 and gate-tunable superconductivity 7 . Whereas the realization of the QSH has demonstrated the nontrivial topology of the electron wavefunctions of monolayer WTe 2 , the geometrical properties of the wavefunction, such as the Berry curvature 9 , remain unstudied. Here we utilize mid-infrared optoelectronic microscopy to investigate the Berry curvature in monolayer WTe 2 . By optically exciting electrons across the inverted QSH gap, we observe an in-plane circular photogalvanic current even under normal incidence. The application of an out-of-plane displacement field allows further control of the direction and magnitude of the photocurrent. The observed photocurrent reveals a Berry curvature dipole that arises from the nontrivial wavefunctions near the inverted gap edge. The Berry curvature dipole and strong electric field effect are enabled by the inverted band structure and tilted crystal lattice of monolayer WTe 2 . Such an electrically switchable Berry curvature dipole may facilitate the observation of a wide range of quantum geometrical phenomena such as the quantum nonlinear Hall 10,11 , orbital-Edelstein 12 and chiral polaritonic effects 13,14 .

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U2 - 10.1038/s41567-018-0189-6

DO - 10.1038/s41567-018-0189-6

M3 - Letter

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EP - 906

JO - Nature Physics

JF - Nature Physics

SN - 1745-2473

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