Photoelectromagnetic Effect Induced by Terahertz Laser Radiation in Topological Crystalline Insulators Pb1−xSnxTe

Topological crystalline insulators form a class of semiconductors for which surface electron states with the Dirac dispersion relation are formed on surfaces with a certain crystallographic orientation. Pb1−xSnxTe alloys belong to the topological crystalline phase when the SnTe content x exceeds 0.35, while they are in the trivial phase at x < 0.35. For the surface crystallographic orientation (111), the appearance of topologically nontrivial surface states is expected. We studied the photoelectromagnetic (PEM) effect induced by laser terahertz radiation in Pb1−xSnxTe films in the composition range x = (0.11–0.44), with the (111) surface crystallographic orientation. It was found that in the trivial phase, the amplitude of the PEM effect is determined by the power of the incident radiation, while in the topological phase, the amplitude is proportional to the flux of laser radiation quanta. A possible mechanism responsible for the effect observed presumes damping of the thermalization rate of photoexcited electrons in the topological phase and, consequently, prevailing of electron diffusion, compared with energy relaxation.

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Discrimination of Conductive Surface Electron States by Laser Terahertz Radiation in PbSe—A Base for Pb$_{1-x}$Sn$_x$Se Topological Crystalline Insulators

IEEE Transactions on Terahertz Science and Technology ◽

10.1109/tthz.2015.2436712 ◽

2015 ◽

Vol 5 (4) ◽

pp. 659-664 ◽

Cited By ~ 2

Author(s):

Svetlana G. Egorova ◽

Vladimir I. Chernichkin ◽

Anna O. Dudnik ◽

Vladimir A. Kasiyan ◽

Leonid Chernyak ◽

...

Keyword(s):

Terahertz Radiation ◽

Surface Electron ◽

Electron States ◽

Conductive Surface ◽

Topological Crystalline Insulators

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Detection of highly conductive surface electron states in topological crystalline insulators Pb1−xSnxSe using laser terahertz radiation

Scientific Reports ◽

10.1038/srep11540 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 20

Author(s):

S. G. Egorova ◽

V. I. Chernichkin ◽

L. I. Ryabova ◽

E. P. Skipetrov ◽

L. V. Yashina ◽

...

Keyword(s):

Terahertz Radiation ◽

Surface Electron ◽

Electron States ◽

Conductive Surface ◽

Topological Crystalline Insulators

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Excitation of transitions between atomic or molecular energy levels by monochromatic laser radiation - II. Excitation under conditions of strictly inhomogeneous line broadening and mixed homogeneous and inhomogeneous broadening

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1978.0117 ◽

1978 ◽

Vol 362 (1708) ◽

pp. 13-25 ◽

Cited By ~ 8

Keyword(s):

Laser Radiation ◽

Line Width ◽

Energy Levels ◽

Incident Radiation ◽

Exciting Radiation ◽

Half Line ◽

Line Broadening ◽

Moment Matrix ◽

Inhomogeneous Line Broadening ◽

Inhomogeneous Line

The development with time of the excitation of a transition between two atomic or molecular energy levels under the influence of monochromatic laser radiation is examined under conditions of strictly inhomogeneous line broadening due to such causes as doppler shift arising from translational velocity. The ratio of the number of molecules, N 2 , in an excited state to the total number, N , is calculated for various ratios of the intensity parameter β ═ E 0 μ / ħ to the half line-width ∆ , where E 0 is the amplitude of the electric field in the incident radiation and is the dipole moment matrix element for the transition. Excitation functions obtained in a previous paper (I) for various values of the ratio γ/β , where γ is the half line-width in the absence of inhomogeneous broadening, are used to obtain the variation of N 2 / N with time under conditions of mixed broadening for various values of the ratio γ/∆ and γ/β , when the exciting radiation is in exact resonance with the central frequency of the transition.

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Symmetry Indicators and Anomalous Surface States of Topological Crystalline Insulators

Physical Review X ◽

10.1103/physrevx.8.031070 ◽

2018 ◽

Vol 8 (3) ◽

Cited By ~ 79

Author(s):

Eslam Khalaf ◽

Hoi Chun Po ◽

Ashvin Vishwanath ◽

Haruki Watanabe

Keyword(s):

Surface States ◽

Anomalous Surface ◽

Topological Crystalline Insulators

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Topological phase and thermoelectric properties of bialkali bismuthide compounds (Na,K)2RbBi from first-principles

Journal of Physics Condensed Matter ◽

10.1088/1361-648x/ac431d ◽

2021 ◽

Author(s):

Shahram Yalameha ◽

Zahra Nourbakhsh ◽

Daryoosh Vashaee

Keyword(s):

Density Functional ◽

Transport Coefficients ◽

Relaxation Times ◽

Surface States ◽

Topological Phase ◽

Boltzmann Transport ◽

Thermoelectric Power Factor ◽

Practical Applications ◽

Wide Range ◽

P Type

Abstract We report the topological phase, thermal, and electrical properties of bialkali bismuthide compounds (Na,K)2RbBi, as yet hypothetical. The topological phase transitions of these compounds under hydrostatic pressure are investigated. The calculated topological surface states and Z2 topological index confirm the nontrivial topological phase. The electronic properties and transport coefficients are obtained using the density functional theory combined with the Boltzmann transport equation. The relaxation times are determined using the deformation potential theory to calculate the electronic thermal and electrical conductivity. The calculated mode Grüneisen parameters are substantial, indicating strong anharmonic acoustic phonons scattering, which results in an exceptionally low lattice thermal conductivity. These compounds also have a favorable thermoelectric power factor leading to a relatively flat p-type figure-of-merit over a broad temperature range. Furthermore, the mechanical properties and phonon band dispersions show that these structures are mechanically and dynamically stable. Therefore, they offer excellent candidates for practical applications over a wide range of temperatures.

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