Snapshots of Dirac fermions near the Dirac point in topological insulators C. W. Luo, H. J. Wang, S. A. Ku [et.al.]
Material type:
ArticleSubject(s): топологические изоляторы | спектроскопия | фермионы | фононы | дираковские точкиGenre/Form: статьи в журналах Online resources: Click here to access online
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Nano letters Vol. 13. P. 5797-5802Abstract: 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 fermionphonon
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.
Библиогр.: 35 назв.
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 fermionphonon
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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