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## Spin Fluctuations at the Surface of Strongly Correlated Topological Insulator SmB6

Applied Magnetic Resonance. 2020. Vol. 51. No. 1. P. 71–84.

S. V. Demishev, Gilmanov M. I., Samarin A. N., Semeno A. V., Sluchanko N. E., Samarin N. A., Bogach A. V., Shitsevalova N. Y., Filipov V. B., Karasev M. S., Glushkov V. V.

The low temperature (T < 5 K) electron spin resonance in topological Kondo insulator SmB6 is investigated. It is shown that spin relaxation time of the paramagnetic centers responsible for low temperature electron spin resonance in SmB6 is about ~ 10−8 s, which exceeds by five orders of magnitude the widely accepted spin and charge fluctuation time ~ 10−13 s in the homogeneous mixed valence state of this material. This discrepancy may be attributed to the formation of the specific paramagnetic centers in the sample surface–spin polarons.

Frolov A. V., Orlov A. P., Sinchenko A. A. et al., Journal of Physics: Conference Series 2018 Vol. 941 P. 1–4

We report preparation of nanoribbons (crossection ~ 250*25 nm2) by focused ion beam etching of single-crystalline Bi2Se3 and detailed measurements of their magnetoresistance at temperatures down to 4.2 K, magnetic field up to 9 T. In a magnetic field parallel to the axis of nanowire the magnetoresistance shows up oscillations. Surprisingly, the Fourier analysis shows ...

Added: February 25, 2018

Овешников Л. Н., Нехаева Е. И., Прудкогляд В. А. et al., Письма в Журнал экспериментальной и теоретической физики 2016 Т. 104 № 9 С. 651–657

В работе исследовалась магнетопроводимость тонких пленок Bi2Se3 с защитным слоем Se, выра
щенных на подложках (111) BaF2. Наблюдаемая отрицательная магнетопроводимость в малых полях,
обусловленная эффектом слабой антилокализации, так же как и осцилляции Шубникова–де Гааза в
больших полях, определяется только перпендикулярной к плоскости пленки компонентой магнитного
поля. Полученные экспериментальные результаты могут быть разумно объяснены в предположении на
личия в исследуемых пленках ...

Added: December 6, 2016

Semeno A. V., Anisimov M. A., Bogach A. V. et al., Scientific Reports 2020 Vol. 10 P. 1–10

Randomness and frustration are believed to be two crucial criteria for the formation of spin glass state. However, the spin freezing occurs in some well-ordered crystals below the related temperature Tf due to the instability of each spin state, which induces the variation of either magnetic moment value or exchange energy. Here we explore the ...

Added: December 25, 2020

Мальшуков А. Г., Physical Review B: Condensed Matter and Materials Physics 2019 Vol. 100 P. 035301-1–035301-7

A nonstationary anomalous Hall current is calculated for a voltage biased Josephson junction, which is composed of two s-wave superconducting contacts deposited on the top of a three-dimensional topological insulator (TI). A homogeneous Zeeman field was assumed at the surface of the TI. The problem has been considered within the ballistic approximation and on the ...

Added: March 11, 2020

Burmistrov I., Repin E., JETP Letters 2015 Vol. 148 No. 3 P. 509

We explore a combined effect of hexagonal warping and a finite effective mass on both the tunneling density of electronic surface states and the structure of Landau levels of 3D topological insulators. We find the increasing warping to transform the square-root van Hove singularity into a logarithmic one. For moderate warping, an additional logarithmic singularity ...

Added: December 3, 2016

Aronzon B. A., Oveshnikov L. N., Prudkoglyad V.A. et al., Journal of Magnetism and Magnetic Materials 2018 Vol. 459 No. 1 P. 331–334

Structural, magnetic and magnetotransport properties of (Bi1-xEux)2Se3 thin films have been studied experimentally as a function of Eu content. The films were synthesized by MBE. It is demonstrated that Eu distribution is not uniform, it enter quint-layers forming inside them plain (pancake-like) areas containing Eu atoms, which sizes and concentration increase with the growth of Eu content. Positive ...

Added: July 13, 2018

Vasenko A. S., Golubov A. A., Silkin V. M. et al., JETP Letters 2017 Vol. 105 No. 8 P. 489–490

We study the effect of the Fermi surface anisotropy (hexagonal warping) on the superconducting pair potential, induced in a three-dimensional topological insulator (TI) by proximity with an s-wave superconductor (S) in presence of a magnetic moment of a nearby ferromagnetic insulator (FI). In the previous studies similar problem was treated with a simplified Hamiltonian, describing ...

Added: April 7, 2017

Glushkov V. V., Demishev S. V., Samarin A. et al., Physica Status Solidi (B): Basic Research 2017 Vol. 254 No. 4 P. 1600571-1–1600571-5

Added: October 19, 2017

A.G. Mal'shukov, Physical Review B: Condensed Matter and Materials Physics 2018 Vol. 97 P. 064515-1–064515-7

It is shown that the spin-orbit and Zeeman interactions result in phase shifts of Andreev-reflected
holes propagating at the surface of a topological insulator, or in Rashba spin-orbit-coupled two
dimensional normal metals, which are in a contact with an s-wave superconductor. Due to interference
of holes reflected through different paths of Andreev interferometer the electric current through
external contacts ...

Added: February 6, 2019

Kuntsevich A., Materials 2022 Vol. 14 No. 24 P. 7528–7528

Search for doped superconducting topological insulators is of prime importance for new quantum technologies. We report on fabrication of Sr-doped Bi2Te3 single crystals. We found that Bridgman grown samples have p-type conductivity in the low 10^19 cm^(−3), high mobility of 4000 cm^2*V^(−1)s^(−1), crystal structure independent on nominal dopant content, and no signs of superconductivity. We also studied molecular ...

Added: June 17, 2022

Alexander P. Protogenov, Verbus V. A., Chulkov E., Physical Review B: Condensed Matter and Materials Physics 2013 Vol. 88 No. 19 P. 195431-1–195431-4

We use the N-terminal scheme for studying the edge-state transport in two-dimensional topological insulators. We find the universal nonlocal response in the ballistic transport approach. This macroscopic exhibition of the topological order offers different areas for applications. ...

Added: December 25, 2013

Mal'shukov A., Physical Review B: Condensed Matter and Materials Physics 2020 Vol. 101 P. 134514-1–134514-7

A nonuniform in-plane Zeeman field can induce spontaneous supercurrents of spin-orbit-coupled electrons in
superconducting two-dimensional systems and thin films. In this work it is shown that current vortices can be
created at the ends of a long homogeneously magnetized strip of a ferromagnetic insulator, which is deposited on
the surface of a three-dimensional topological insulator. The s-wave superconductivity ...

Added: January 20, 2021

Verbus V. A., Protogenov A. P., Chulkov E., / Cornell University. Series cond-mat "arxiv.org". 2014. No. 1406.1507.

Weyl semimetal is a three-dimensional material with a conical spectrum near an even number of point nodes, where two bands touch each other. Here we study spectral properties of surface electron states in such a system. We show that the density of surface states possesses a logarithmic singularity for the energy to 0. It decreases ...

Added: March 8, 2016

T. Karabassov, A.A. Golubov, Silkin V. M. et al., Physical Review B: Condensed Matter and Materials Physics 2021 Vol. 103 P. 224508-1–224508-9

Superconducting hybrid structures with topological order and induced magnetization offer a promising way to realize fault-tolerant quantum computation. However, the effect of the interplay between magnetization and the property of the topological insulator surface, otherwise known as spin-momentum locking on the superconducting proximity effect, still remains to be investigated. We relied on the quasiclassical self-consistent ...

Added: June 4, 2021

Kuntsevich A., Shupletsov A. V., Minkov G. M., Physical Review B: Condensed Matter and Materials Physics 2018 Vol. 97 P. 195431-1–195431-8

The phase of quantum magneto-oscillations is often associated with the Berry phase and is widely used to
argue in favor of topological nontriviality of the system (Berry phase 2πn + π). Nevertheless, the experimentally
determined value may deviate from 2πn + π arbitrarily, therefore more care should be made analyzing the
phase of magneto-oscillations to distinguish trivial systems ...

Added: September 10, 2018

Demishev S. V., Krasnorussky V., Bogach A. et al., Scientific Reports 2017 Vol. 7 P. 17430-1–17430-8

Spatial anisotropy generated spontaneously in the translationally invariant metallic phase, i.e. electron nematic efect, addresses a great challenge for both experimentalists and theoreticians. An interesting option for the realization of the electron nematic phase is provided by the system with orbital ordering, as long as both orbitally ordered states and electron nematic phases possess broken ...

Added: March 10, 2018

Karabassov T., Vasenko A., Известия Уфимского научного центра РАН 2021 Т. 1 С. 10–16

Materials that possess strong spin-orbit interaction have provoked great interest over the past few years, in
particular, in the actively developing field of quantum calculations. A topological insulator is a good example of
such a material. The topological insulator has high surface conductivity, whereas in the body it shows the properties
of an insulator, this being a purely ...

Added: December 30, 2020

Backens S., Shnirman A., Makhlin Y., JETP Letters 2022 Vol. 116 No. 12 P. 891–895

We consider Majorana zero modes in a Josephson junction on top of a topological insulator in transverse magnetic field. Majorana zero modes reside at periodically located nodes of Josephson vortices. We find that hybridization of these modes is prohibited by symmetries of the problem at vanishing chemical potential, which ensures better protection of zero modes ...

Added: December 10, 2022

Pudalov V., Сахин В. О., Куковицкий Е. Ф. et al., Письма в Журнал экспериментальной и теоретической физики 2022 Т. 115 № 4 С. 270–276

The formation of nanosized charge droplets in the bulk of a three-dimensional topological insulator
Bi1.08Sn0.02Sb0.9Te2S was evidenced using electron spin resonance. Since electrons and holes are “locked” in
these droplets far apart from each other, their participation in bulk conductivity is possible only due to thermal
activation or to variable range hopping. Our transport measurements give evidence that ...

Added: November 16, 2022

Sosin S., Яфарова А. Ф., Романова И. В. et al., Письма в Журнал экспериментальной и теоретической физики 2022 Т. 116 № 11-12 С. 747–755

Low-temperature electron paramagnetic resonance measurements are performed on single crystals of LiY1 – xGdxF4 with low x = 0.005 and moderate x = 0.05 concentration of Gd ions. Modeling of the experimental spectra allows us to precisely determine microscopic parameters of the spin Hamiltonian of the parent LiGdF4 material, including the nearest-neighbor exchange constant. The obtained parameters ...

Added: December 7, 2022

Antipov A., Seleznev V., Vakhtomin Y. et al., IOP Conference Series: Materials Science and Engineering (MSE) 2020 Vol. 781 No. 1 P. 012011-1–012011-5

Spectral characteristics of WSi and NbN superconducting single-photon detectors with different surface resistance and width of nanowire strips have been investigated in the wavelength range of 1.3-2.5 µm. WSi structures with narrower strips demonstrated better performance for detection of single photons in longer wavelength range. The difference in normalized photon count rate for such structures ...

Added: December 10, 2020

Budkov Y., Kolesnikov A. L., Polymer Science - Series C 2018 Vol. 60 No. Supplement 1 P. 148–159

Theoretical models of the conformational behavior of flexible polymer chains in mixed solvents enunciated in the world literature during the last decade are critically reviewed. Models describing different mechanisms of coil-to-globule transitions in a good solvent induced by cosolvent addition are highlighted. Special attention is given to the analysis of theoretical approaches to describing the ...

Added: November 30, 2018

Kalmykov A., Melentiev P., Balykin V., Laser Physics Letters 2020 Vol. 17 No. 4 P. 045901

In this paper we present measurements and comparison of SPP propagation length at the practically important telecom wavelength (1560 nm) as well as in the near-infrared and visible spectral ranges. The measurements were carried out for plane SPP waves excited on Ag film surface using optical microscopy of SPP waves in the far field. We ...

Added: January 15, 2021

M.: Faculty of Physics, MSU, 2017

The Low Temperature Physics Conference is an international event held every three years, under the auspices of the IUPAP through its Commission C5 on Low Temperature Physics. The aim of these conferences is to exchange information and views among the members of the international scientific community in the general field of Low Temperature Physics. It ...

Added: October 1, 2017