Abstract
In this paper, we show that electron states formed in topological insulators at the interfaces topological phase–trivial phase and topological phase–vacuum may possess different properties. ...This is demonstrated on an example of heterostructures based on thick topological Hg
1−
x
Cd
x
Te films, in which the
PT
-symmetric terahertz photoconductivity is observed. It is shown that the effect originates from features of the interface topological film–trivial buffer/cap layer. The
PT
-symmetric terahertz photoconductivity is not provided by electron states formed at the interface topological film–vacuum.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The
PT
-symmetric photoconductivity has been detected for the first time in microwave-irradiated heterostructures based on thick Hg
1 −
x
Cd
x
Te films with the CdTe content
x
corresponding to the ...topological phase although the magnetic field symmetry (
T
symmetry) and the symmetry in the positions of potential contact pairs (
P
symmetry) are not conserved separately. The microwave photoconductivity in similar heterostructures based on the trivial Hg
1 −
x
Cd
x
Te phase is both
P
- and
T
-symmetric.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
It is demonstrated that the
PT
-symmetric terahertz photoconductivity observed in heterostructures based on thick Hg
1 –
x
Cd
x
Te films in the topological phase is due to the photoexcitation of ...charge carriers in the film bulk. At the same time, the place of localization of the effect is the topological film–trivial buffer layer heterointerface. The model describing such a spatial separation of the source of nonequilibrium charge carriers and the effect localization is discussed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
We report on observation of strong non-local photoconducitivity induced by terahertz laser pulses in non-zero magnetic field in heterostructures based on Hg
1−
x
Cd
x
Te films being in the ...topological phase. While the zero-field non-local photoconductivity is negligible, it is strongly enhanced in magnetic fields ~ 0.05 T resulting in appearance of an edge photocurrent that exceeds the respective dark signal by orders of magnitude. This photocurrent is chiral, and the chirality changes every time the magnetic field or the electric bias is reversed. Appearance of the non-local terahertz photoconductivity is attributed to features of the interface between the topological film and the trivial buffer.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
An experimental study is performed of the differences between the electronic states necessarily formed at the boundaries of a topological phase in a vacuum and a trivial buffer in the regions of ...heterojunction in topological materials based on Hg
1 –
x
Cd
x
Te epitaxial films. It is shown that the
PT
-symmetric terahertz photoconductivity observed in the specified structures is due precisely to states in the region of topological film/trivial buffer (or cap layer) interfaces.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
6.
First cage-like pentanuclear Co(ii)-silsesquioxane Bilyachenko, A N; Yalymov, A I; Levitsky, M M ...
Dalton transactions : an international journal of inorganic chemistry,
01/2016, Volume:
45, Issue:
35
Journal Article
Peer reviewed
A new pentanuclear "cylinder"-like cobalt(ii) phenylsilsesquioxane (PhSiO1.5)10(CoO)5(NaOH) exhibits a slow relaxation of the magnetization and a high catalytic activity and stereoselectivity in the ...oxidation of alkanes and alcohols.
Microwave Photoconductivity in Hg1 –xCdxTe Chmyr’, S. N.; Kazakov, A. S.; Galeeva, A. V. ...
Bulletin of the Russian Academy of Sciences. Physics,
06/2023, Volume:
87, Issue:
6
Journal Article
Peer reviewed
Positive photoconductivity stimulated by microwave radiation has been observed in Hg
1 –
x
Cd
x
Te thick films being in the topological phase at
x
< 0.16. The effect amplitude is significant at the ...liquid helium temperatures, and rapidly decreases with the temperature rising. A mechanism for the positive photoconductivity appearance in the topological phase films is suggested.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We report on the stimulated emission obtained in the wavelength range of 20.3–17.4 μm on the interband transitions at
T
= 8–50 K in HgCdTe quantum wells placed in a dielectric waveguide formed from ...wide-gap CdHgTe solid solution. Heterostructures with HgCdTe quantum wells are interesting for designing long-wavelength lasers operating in the wavelength range of 25–60 μm, which is not covered by currently available quantum cascade lasers. It is shown that the maximum temperature of stimulated emission is determined by the position of lateral maxima in the dispersion dependences in the first valence subband of the quantum well. Methods for suppressing nonradiative recombination in the structures with HgCdTe quantum wells are discussed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The device and principle of operation of the “Microscope” stand for determining the measurement error of reflecting-surface movements are described. The stand is developed on the basis of a BMI-1 ...instrumental microscope; a glass line measure of the second accuracy class is used as the comparison standard. A theoretical assessment of the measurement error of the reflecting-surface movement using the “Microscope” stand is given. The technique of verification of microwave radio interferometers using the developed stand and the results of determining the error of the microwave radio interferometer according to the presented method are presented.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Theoretical issues, guidelines and practical suggestions for diagnosing the management of material flows of a manufacturing enterprise using the example of "KraMZ" are discussed in the article. The ...following tasks in accordance with the purpose of the study were formulated: to develop and study the material flow management system of the production enterprise "KraMZ", to evaluate the functioning efficiency of the developed material flow management system of this enterprise.
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