Terahertz properties of Dirac fermions in HgTe films with optical doping

Dziom, V.; Shuvaev, A.; Михайлов, Н. Н.; Pimenov, A.

doi:10.1088/2053-1583/aa5cd7

Cited by 13 publications

(16 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After a calibration to absolute values, the complex polarization rotation angle θ + iη can be calculated either using the simplified Equations ( 1) and ( 2) or via the exact procedure [18][19][20]. Complex polarization rotation angles at the lowest temperature of our experiments (T = 1.85 K) and at various frequencies are shown in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

“…Full expressions for the polarization rotation include the influence of the substrate and are given elsewhere [18][19][20]. However, two important approximations substantially simplify the interpretation of the data.…”

Section: Introductionmentioning

confidence: 99%

“…This indicates that the resonance terms in the Drude conductivity with typical width ωτ are negligible. In the same approximation the (Faraday) rotation angle θ can be written as [18][19][20]:…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Faraday Rotation Due to Quantum Anomalous Hall Effect in Cr-Doped (Bi,Sb)2Te3

et al. 2021

View full text Add to dashboard Cite

Quantum anomalous Hall effect (QAHE) represents a quantized version of the classical anomalous Hall effect. In the latter case the magnetization takes over the role of magnetic field and induces nonzero off-diagonal elements in the conductivity matrix. In magnetic topological insulators with the band inversion the QAHE can be reached due to quantized conduction channel at the sample edge if the Fermi energy is tuned into the surface magnetic gap. In the static regime the QAHE is seen as a zero-field step in the Hall resistivity. At optical frequencies this step is transformed into a quantized value of the polarization rotation approaching the fine structure constant α=e2/2ε0hc≈1/137. However, due to material issues the steps reach the predicted values at millikelvin temperatures only. In this work we investigate the Faraday polarization rotation in thin films of Cr-doped topological insulator and in the sub-terahertz frequency range. Well defined polarization rotation steps can be observed in transmittance in Faraday geometry. At temperatures down to T=1.85 K the value of the rotation reached about 20% of the fine structure constant and disappeared completely for T>20 K.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Faraday Rotation Due to Quantum Anomalous Hall Effect in Cr-Doped (Bi,Sb)2Te3

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The CR response in the investigated systems was studied using magneto-optical transmission technique with controlled polarization of light [23,24]. Backwardwave oscillators were employed to produce continuous monochromatic light in the frequency range 100 GHz -1000 GHz.…”

Section: B Techniquementioning

confidence: 99%

Energy spectrum of semimetallic HgTe quantum wells

Gospodaric,

Shuvaev,

Mikhailov

et al. 2021

Preprint

View full text Add to dashboard Cite

Quantum wells (QWs) based on mercury telluride (HgTe) thin films provide a large scale of unusual physical properties starting from an insulator via a two-dimensional Dirac semimetal to a three-dimensional topological insulator. These properties result from the dramatic change of the QW band structure with the HgTe film thickness. Although being a key property, these energy dispersion relations cannot be reflected in experiments due to the lack of appropriate tools. Here we report an experimental and theoretical study of two HgTe quantum wells with inverted energy spectrum in which two-dimensional semimetallic states are realized. Using magneto-optical spectroscopy at sub-THz frequencies we were able to obtain information about electron and hole cyclotron masses at all relevant Fermi level positions and different charge densities. The outcome is also supported by a Shubnikov-de Haas analysis of capacitance measurements, which allows obtaining information about the degeneracy of the active modes. From these data, it is possible to reconstruct electron and hole dispersion relations. Detailed comparative analysis of the energy dispersion relations with theoretical calculations demonstrates a good agreement, reflecting even several subtle features like band splitting, the second conduction band, and the overlaps between the first conduction and first valence band. Our study demonstrates that the cyclotron resonance experiments can be efficiently used to directly obtain the band structures of semimetallic 2D materials.

show abstract

“…(a,b)) increases approximately linearly with the density of electrons and holes, indicating a Electrodynamic parameters of the charge carriers. The data are obtained from simultaneous fitting of the magneto-optical spectra using the Drude model in the presence of the external magnetic field[28,35]. Left panels -sample # 1 (340 GHz), d = 6.3 nm, right panelssample # 2 (320 GHz), d = 6.6 nm.…”

mentioning

confidence: 99%

Band structure of a two-dimensional Dirac semimetal from cyclotron resonance

Shuvaev¹,

Dziom²,

Михайлов³

et al. 2017

Phys. Rev. B

View full text Add to dashboard Cite

Knowing the band structure of materials is one of the prerequisites to understand their properties.Therefore, especially in the last decades, angle-resolved photoemission spectroscopy (ARPES) has become a highly demanded experimental tool to investigate the band structure. However, especially in thin film materials with a layered structure and several capping layers, access to the electronic structure by ARPES is limited. Therefore, several alternative methods to obtain the required information have been suggested. Here, we directly invert the results by cyclotron resonance experiments to obtain the band structure of a two-dimensional (2D) material. This procedure is applied to the mercury telluride quantum well with critical thickness which is characterized by a 2D electron gas with linear dispersion relations. The Dirac-like band structure in this material could be mapped both on the electron and on the hole side of the band diagram. In this material, purely linear dispersion of the hole-like carriers is in contrast to detectable quadratic corrections for the electrons.

show abstract

Terahertz properties of Dirac fermions in HgTe films with optical doping

Cited by 13 publications

References 26 publications

Faraday Rotation Due to Quantum Anomalous Hall Effect in Cr-Doped (Bi,Sb)2Te3

Faraday Rotation Due to Quantum Anomalous Hall Effect in Cr-Doped (Bi,Sb)2Te3

Energy spectrum of semimetallic HgTe quantum wells

Band structure of a two-dimensional Dirac semimetal from cyclotron resonance

Contact Info

Product

Resources

About