Snapshots of Dirac fermions near the Dirac point in topological insulators

Chih-Wei Luo; H. J. Wang; S. A. Ku; H. J. Chen; T. T. Yeh; Jiunn-Yuan Lin; Kaung-Hsiung Wu; Jenh-Yih Juang; Ben-Li Young; Takayoshi Kobayashi; C. M. Cheng; C. H. Chen; K. D. Tsuei; R. Sankar; F. C. Chou; K. A. Kokh; O. E. Tereshchenko; E. V. Chulkov; Yu M. Andreev; G. D. Gu

doi:10.1021/nl4021842

Snapshots of Dirac fermions near the Dirac point in topological insulators

Chih-Wei Luo^*, H. J. Wang, S. A. Ku, H. J. Chen, T. T. Yeh, Jiunn-Yuan Lin, Kaung-Hsiung Wu, Jenh-Yih Juang, Ben-Li Young, Takayoshi Kobayashi, C. M. Cheng, C. H. Chen, K. D. Tsuei, R. Sankar, F. C. Chou, K. A. Kokh, O. E. Tereshchenko, E. V. Chulkov, Yu M. Andreev, G. D. Gu

^*Corresponding author for this work

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

61 Scopus citations

Abstract

The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.

Original language	English
Pages (from-to)	5797-5802
Number of pages	6
Journal	Nano Letters
Volume	13
Issue number	12
DOIs	https://doi.org/10.1021/nl4021842
State	Published - 11 Dec 2013

Keywords

Dirac fermion dynamics
Dirac fermion-phonon coupling
Topological insulator
ultrafast optical pump mid-infrared probe spectroscopy
DYNAMICS

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10.1021/nl4021842

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Luo, C-W., Wang, H. J., Ku, S. A., Chen, H. J., Yeh, T. T., Lin, J-Y., Wu, K-H., Juang, J-Y., Young, B-L., Kobayashi, T., Cheng, C. M., Chen, C. H., Tsuei, K. D., Sankar, R., Chou, F. C., Kokh, K. A., Tereshchenko, O. E., Chulkov, E. V., Andreev, Y. M., & Gu, G. D. (2013). Snapshots of Dirac fermions near the Dirac point in topological insulators. Nano Letters, 13(12), 5797-5802. https://doi.org/10.1021/nl4021842

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title = "Snapshots of Dirac fermions near the Dirac point in topological insulators",

abstract = "The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.",

keywords = "Dirac fermion dynamics, Dirac fermion-phonon coupling, Topological insulator, ultrafast optical pump mid-infrared probe spectroscopy, DYNAMICS",

author = "Chih-Wei Luo and Wang, {H. J.} and Ku, {S. A.} and Chen, {H. J.} and Yeh, {T. T.} and Jiunn-Yuan Lin and Kaung-Hsiung Wu and Jenh-Yih Juang and Ben-Li Young and Takayoshi Kobayashi and Cheng, {C. M.} and Chen, {C. H.} and Tsuei, {K. D.} and R. Sankar and Chou, {F. C.} and Kokh, {K. A.} and Tereshchenko, {O. E.} and Chulkov, {E. V.} and Andreev, {Yu M.} and Gu, {G. D.}",

year = "2013",

month = dec,

day = "11",

doi = "10.1021/nl4021842",

language = "English",

volume = "13",

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Luo, C-W, Wang, HJ, Ku, SA, Chen, HJ, Yeh, TT, Lin, J-Y, Wu, K-H, Juang, J-Y , Young, B-L , Kobayashi, T, Cheng, CM, Chen, CH, Tsuei, KD, Sankar, R, Chou, FC, Kokh, KA, Tereshchenko, OE, Chulkov, EV, Andreev, YM & Gu, GD 2013, 'Snapshots of Dirac fermions near the Dirac point in topological insulators', Nano Letters, vol. 13, no. 12, pp. 5797-5802. https://doi.org/10.1021/nl4021842

TY - JOUR

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AU - Luo, Chih-Wei

AU - Wang, H. J.

AU - Ku, S. A.

AU - Chen, H. J.

AU - Yeh, T. T.

AU - Lin, Jiunn-Yuan

AU - Wu, Kaung-Hsiung

AU - Juang, Jenh-Yih

AU - Young, Ben-Li

AU - Kobayashi, Takayoshi

AU - Cheng, C. M.

AU - Chen, C. H.

AU - Tsuei, K. D.

AU - Sankar, R.

AU - Chou, F. C.

AU - Kokh, K. A.

AU - Tereshchenko, O. E.

AU - Chulkov, E. V.

AU - Andreev, Yu M.

AU - Gu, G. D.

PY - 2013/12/11

Y1 - 2013/12/11

N2 - The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.

AB - The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.

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VL - 13

SP - 5797

EP - 5802

JO - Nano Letters

JF - Nano Letters

IS - 12

ER -

Snapshots of Dirac fermions near the Dirac point in topological insulators

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Keywords

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