Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser

S. Gerber; S. L. Yang; D. Zhu; H. Soifer; J. A. Sobota; S. Rebec; J. J. Lee; T. Jia; B. Moritz; C. Jia; A. Gauthier; Y. Li; D. Leuenberger; Y. Zhang; L. Chaix; W. Li; H. Jang; J. S. Lee; M. Yi; G. L. Dakovski; S. Song; J. M. Glownia; S. Nelson; K. W. Kim; Y. D. Chuang; Z. Hussain; R. G. Moore; T. P. Devereaux; W. S. Lee; P. S. Kirchmann; Z. X. Shen

doi:10.1126/science.aak9946

Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser

S. Gerber, S. L. Yang, D. Zhu, H. Soifer, J. A. Sobota, S. Rebec, J. J. Lee, T. Jia, B. Moritz, C. Jia, A. Gauthier, Y. Li, D. Leuenberger, Y. Zhang, L. Chaix, W. Li, H. Jang, J. S. Lee, M. Yi, G. L. DakovskiS. Song, J. M. Glownia, S. Nelson, K. W. Kim, Y. D. Chuang, Z. Hussain, R. G. Moore, T. P. Devereaux, W. S. Lee^*, P. S. Kirchmann, Z. X. Shen

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

201 Scopus citations

Abstract

The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a “coherent lock-in” measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.

Original language	English
Pages (from-to)	71-75
Number of pages	5
Journal	Science
Volume	357
Issue number	6346
DOIs	https://doi.org/10.1126/science.aak9946
State	Published - 7 Jul 2017
Externally published	Yes

Funding

Funders	Funder number
National Research Foundation of Korea
Division of Materials Sciences and Engineering
LCLS
Stanford University
National Defense Science and Engineering Graduate
U.S. Department of Energy
Stanford Institute for Materials and Energy Sciences
Office of Science
Ministry of Science, ICT and Future Planning	NRF-2015R1A2A1A10056200, DE-AC02-05CH11231
Basic Energy Sciences	DE-AC02-76SF00515
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung	P2EZP2_148737, 148737, P300P2_151328

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Gerber, S., Yang, S. L., Zhu, D., Soifer, H., Sobota, J. A., Rebec, S., Lee, J. J., Jia, T., Moritz, B., Jia, C., Gauthier, A., Li, Y., Leuenberger, D., Zhang, Y., Chaix, L., Li, W., Jang, H., Lee, J. S., Yi, M., ... Shen, Z. X. (2017). Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser. Science, 357(6346), 71-75. https://doi.org/10.1126/science.aak9946

@article{2994701e1b844fc5a8f2d5b5ad5839c6,

title = "Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser",

abstract = "The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a “coherent lock-in” measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.",

author = "S. Gerber and Yang, {S. L.} and D. Zhu and H. Soifer and Sobota, {J. A.} and S. Rebec and Lee, {J. J.} and T. Jia and B. Moritz and C. Jia and A. Gauthier and Y. Li and D. Leuenberger and Y. Zhang and L. Chaix and W. Li and H. Jang and Lee, {J. S.} and M. Yi and Dakovski, {G. L.} and S. Song and Glownia, {J. M.} and S. Nelson and Kim, {K. W.} and Chuang, {Y. D.} and Z. Hussain and Moore, {R. G.} and Devereaux, {T. P.} and Lee, {W. S.} and Kirchmann, {P. S.} and Shen, {Z. X.}",

note = "Publisher Copyright: {\textcopyright} The Authors",

year = "2017",

month = jul,

day = "7",

doi = "10.1126/science.aak9946",

language = "אנגלית",

volume = "357",

pages = "71--75",

journal = "Science",

issn = "0036-8075",

publisher = "American Association for the Advancement of Science",

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Gerber, S, Yang, SL, Zhu, D, Soifer, H, Sobota, JA, Rebec, S, Lee, JJ, Jia, T, Moritz, B, Jia, C, Gauthier, A, Li, Y, Leuenberger, D, Zhang, Y, Chaix, L, Li, W, Jang, H, Lee, JS, Yi, M, Dakovski, GL, Song, S, Glownia, JM, Nelson, S, Kim, KW, Chuang, YD, Hussain, Z, Moore, RG, Devereaux, TP, Lee, WS, Kirchmann, PS & Shen, ZX 2017, 'Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser', Science, vol. 357, no. 6346, pp. 71-75. https://doi.org/10.1126/science.aak9946

TY - JOUR

T1 - Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser

AU - Gerber, S.

AU - Yang, S. L.

AU - Zhu, D.

AU - Soifer, H.

AU - Sobota, J. A.

AU - Rebec, S.

AU - Lee, J. J.

AU - Jia, T.

AU - Moritz, B.

AU - Jia, C.

AU - Gauthier, A.

AU - Li, Y.

AU - Leuenberger, D.

AU - Zhang, Y.

AU - Chaix, L.

AU - Li, W.

AU - Jang, H.

AU - Lee, J. S.

AU - Yi, M.

AU - Dakovski, G. L.

AU - Song, S.

AU - Glownia, J. M.

AU - Nelson, S.

AU - Kim, K. W.

AU - Chuang, Y. D.

AU - Hussain, Z.

AU - Moore, R. G.

AU - Devereaux, T. P.

AU - Lee, W. S.

AU - Kirchmann, P. S.

AU - Shen, Z. X.

PY - 2017/7/7

Y1 - 2017/7/7

N2 - The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a “coherent lock-in” measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.

AB - The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a “coherent lock-in” measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.

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DO - 10.1126/science.aak9946

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SN - 0036-8075

VL - 357

SP - 71

EP - 75

JO - Science

JF - Science

IS - 6346

ER -

Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser

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