Strong interband Faraday rotation in 3D topological insulator Bi2Se3

Ohnoutek, Lukáš; Hakl, Michael; Veis, Martin; Piot, B. A.; Faugeras, C.; Martinez, G.; Yakushev, М. V.; Martin, Robert; Drašar, Č.; Materna, A.; Strzelecka, G.; Hruban, A.; Potemski, M.; Орлита, М.

doi:10.1038/srep19087

Cited by 18 publications

(26 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Bi 2 Se 3 , after the correction for the Burstein-Moss effect, we find a bandgap value of 215 ± 10 meV at 10 K in good agreement with the values from 190 to 220 meV reported in the literature 13,19,25,39 . Our result supports the conclusion of ARPES 7 , GW calculations 46,47 and SdH measurements 37 that the direct bandgap of Bi 2 Se 3 is located at the Γ point in the Brillouin zone, the valence band reaches up to the Dirac point and has a shape of a downward oriented paraboloid.…”

Section: Discussionsupporting

confidence: 90%

“…Below the onset of interband transitions at low temperature, ε 2 is zero within the uncertainty of the analysis. This is consistent with the observed transmission values up to 14% measured on 225 µm thick single crystal 25 , which is possible only if ε 2 0.1. Due to a significant concentration of free electrons, the Fermi level, E F , lies in the conduction band.…”

Section: B the Absorption Edge In Bi2se3supporting

confidence: 92%

“…In our data, the shift of the absorption edge between 80 and 10 K is about 35 meV. When taking into account this value, we obtain E 19 From a recent transmission experiment on single crystals, Ohnoutek et al 25 reported E direct g ≈ 200 meV. Notably, a very recent work 39 combining luminescence, transmission and magneto-transport measurements estimated that the gap value is 220 ± 5 meV which agrees within the errorbars with our result.…”

Section: B the Absorption Edge In Bi2se3supporting

confidence: 89%

“…Even the surface states [21][22][23][24] and strong Faraday rotation 25 have been observed by infrared spectroscopy. Despite the large experimental effort, several questions remain open.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Interband absorption edge in the topological insulators Bi2(Te1−xSex)3

et al. 2017

Self Cite

View full text Add to dashboard Cite

We have investigated the optical properties of thin films of topological insulators Bi2Te3, Bi2Se3 and their alloys Bi2(Te1−xSex)3 on BaF2 substrates by a combination of infrared ellipsometry and reflectivity in the energy range from 0.06 to 6.5 eV. For the onset of interband absorption in Bi2Se3, after the correction for the Burstein-Moss effect, we find the value of direct bandgap of 215±10 meV at 10 K. Our data supports the picture that Bi2Se3 has a direct band gap located at the Γ point in the Brillouin zone and that the valence band reaches up to the Dirac point and has the shape of a downward oriented paraboloid, i.e. without a camel-back structure. In Bi2Te3, the onset of strong direct interband absorption at 10 K is at a similar energy of about 200 meV, with a weaker additional feature at about 170 meV. Our data support the recent GW band structure calculations suggesting that the direct interband transition does not occur at the Γ point but near the Z-F line of the Brillouin zone. In the Bi2(Te1−xSex)3 alloy, the energy of the onset of direct interband transitions exhibits a maximum near x = 0.3 (i.e. the composition of Bi2Te2Se), suggesting that the crossover of the direct interband transitions between the two points in the Brillouin zone occurs close to this composition.

show abstract

Section: Discussionsupporting

confidence: 90%

Section: B the Absorption Edge In Bi2se3supporting

confidence: 92%

Section: B the Absorption Edge In Bi2se3supporting

confidence: 89%

“…Even the surface states [21][22][23][24] and strong Faraday rotation 25 have been observed by infrared spectroscopy. Despite the large experimental effort, several questions remain open.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Interband absorption edge in the topological insulators Bi2(Te1−xSex)3

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…These media exhibit electromagnetic cross-correlation effects due to the momentum-dependent spin-orbit interaction and, thus, a rich variety of optical phenomena can be expected [1][2][3][4][5][6][7][8][9][10] . Among them, optical phenomena induced by the spatial dispersion and/or magnetization in media lacking space inversion and/or time reversal symmetries are important for elucidating the electromagnetic responses of electrons.…”

Section: Introductionmentioning

confidence: 99%

Theory of electromagnetic wave propagation in ferromagnetic Rashba conductor

Shibata

Takeuchi

Kohno

et al. 2018

Journal of Applied Physics

View full text Add to dashboard Cite

We present a comprehensive study of various electromagnetic wave propagation phenomena in a ferromagnetic bulk Rashba conductor from the perspective of quantum mechanical transport. In this system, both the space inversion and time reversal symmetries are broken, as characterized by the Rashba field α and magnetization M , respectively. First, we present a general phenomenological analysis of electromagnetic wave propagation in media with broken space inversion and time reversal symmetries based on the dielectric tensor. The dependence of the dielectric tensor on the wave vector q and M are retained to first order. Then, we calculate the microscopic electromagnetic response of the current and spin of conduction electrons subjected to α and M , based on linear response theory and the Green's function method; the results are used to study the system optical properties. Firstly, it is found that a large α enhances the anisotropic properties of the system and enlarges the frequency range in which the electromagnetic waves have hyperbolic dispersion surfaces and exhibit unusual propagations known as negative refraction and backward waves. Secondly, we consider the electromagnetic cross-correlation effects (direct and inverse Edelstein effects) on the wave propagation. These effects stem from the lack of space inversion symmetry and yield q-linear off-diagonal components in the dielectric tensor. This induces a Rashba-induced birefringence, in which the polarization vector rotates around the vector (α × q). In the presence of M , which breaks time reversal symmetry, there arises an anomalous Hall effect and the dielectric tensor acquires off-diagonal components linear in M . For α M , these components yield the Faraday effect for the Faraday configuration q M , and the Cotton-Mouton effect for the Voigt configuration (q ⊥ M ). When α and M are noncollinear, M -and q-induced optical phenomena are possible, which include nonreciprocal directional dichroism in the Voigt configuration. In these nonreciprocal optical phenomena, a "toroidal moment," α × M , and a "quadrupole moment," αiMj + αjMi, play central roles. These phenomena are strongly enhanced at the spin-split transition edge in the electron band.

show abstract