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## Nonlinear focusing of terahertz laser beam using a layered superconductor

Physical Review B: Condensed Matter and Materials Physics. 2022. Vol. 106. No. 17. Article 174511.

Ovcharenko H. V., Maizelis Z. A., Apostolov S. S., Yampol’skii V. A.

We theoretically study the propagation of a terahertz (THz) Gaussian beam through a thin sample of layered superconductor. We consider the beam axis and the superconducting layers to be perpendicular to the sample interface, while the electric field in the beam is perpendicular to the layers. We show that, in such a geometry, the Josephson current between the superconducting layers supports lensing of the beam instead of divergence on the Rayleigh range. Moreover, due to the nonlinearity, the focal length and waist of the transmitted beam depend on the incident beam intensity. These dependencies demonstrate nontrivial hysteresis behavior that can be observed in experiments with THz lasers.

Pudalov V. M., Kuzmicheva T. E., Sadakov A. V. et al., JETP Letters (Германия) - полный текст, 7 стр. 2016 Vol. 104 No. 12 P. 864-864

We present direct measurements of the superconducting order parameter in nearly optimal FeSe Te single crystals with the critical temperature TC ≈ 14 K. Using the intrinsic multiple Andreev reflection effect (IMARE) spectroscopy and measurements of the lower critical field, we directly determined two superconducting gaps, ΔL ≈ 3.3−3.4 meV and ΔS ≈ 1 meV, ...

Added: February 23, 2017

Кузьмичева Т. Е., Кузьмичев С. А., Кордюк А. А. et al., JETP Letters, USA 2018 Т. 107 № 1 С. 47-53

The superconducting order parameters in optimally doped Ba0.65K0.35Fe2As2 single crystals have been directly measured using multiple Andreev reflection effect spectroscopy of superconductor–normal metal–superconductor break-junctions. We determine two superconducting gaps, which are nodeless in the kx-ky-plane of the momentum space, and resolve a substantial in-plane anisotropy of the large gap. The temperature dependences of the gaps ...

Added: August 4, 2018

Mal'shukov A., Physical Review B: Condensed Matter and Materials Physics 2020 Vol. 102 P. 134509-1-134509-5

The Zeeman interaction results in spontaneous current through a Josephson contact with a spin-orbit coupled
normal metal, even in the absence of any voltage, or phase bias. In the case of the Rashba spin-orbit coupling
of electrons in a two-dimensional (2D) electron gas this effect takes place for the Zeeman field which is parallel
to the 2D system ...

Added: January 20, 2021

Kagan M., Bianconi A., Condensed Matter, MDPI Publisher, Switzerland 2019 Vol. 4(2) No. 51 P. 1-19

In this review article we consider theoretically and give experimental support to the models of the Fermi-Bose mixtures and the BCS-BEC (Bardeen Cooper Schrieffer–Bose Einstein) crossover compared with the strong-coupling approach, which can serve as the cornerstones on the way from high-temperature to room-temperature superconductivity in pressurized metallic hydrides. We discuss some key theoretical ideas ...

Added: May 16, 2019

Arutyunov K., Lehtinen J. S., Beilstein Journal of Nanotechnology 2020 Vol. 11 P. 417-420

Chain of superconductor-insulator-superconductor junctions based on Al-AlOx-Al... lift-off fabricated nanostructures was measured at ultra-low temperatures. At zero magnetic field the low current bias dynamic resistance can reach values ~1011 W. The system has been proved to provide a decent quality current biasing circuit enabling observation of Coulomb blockade and Bloch oscillations in ultra-narrow Ti nanowires ...

Added: September 18, 2020

К.И. Кугель, Бабушкина Н. А., Владимиров А. А. et al., Журнал экспериментальной и теоретической физики 2020 Т. 158 № 4 С. 714-727

Abstract—Experimental data on the temperature dependence of electrical resistivity are analyzed for electrondoped Nd2–xCexCuO4–δ cuprates in a wide range of cerium concentrations 0.12 ≤ x ≤ 0.20. It is shown that, in a wide temperature range above the superconducting transition temperature, the electrical resistivity mainly exhibits quadratic temperature dependence and decreases sharply at concentrations of ...

Added: December 6, 2020

Osin A. S., Fominov Ya.V., Physical Review B: Condensed Matter and Materials Physics 2021 Vol. 104 No. 6 Article 064514

We consider a planar SIS-type Josephson junction between diffusive superconductors (S) through an insulating tunnel interface (I). We construct fully self-consistent perturbation theory with respect to the interface conductance. As a result, we find correction to the first Josephson harmonic and calculate the second Josephson harmonic. At arbitrary temperatures, we correct previous results for the ...

Added: September 2, 2021

Sasaki A., Ikegaya S., Habe T. et al., Physical Review B: Condensed Matter and Materials Physics 2020 Vol. 101 No. 184501 P. 184501-1-184501-6

We study theoretically the Josephson effect between two two-band superconductors respecting time-reversal
symmetry, where we assume a spin-singlet s-wave pair potential in each conduction band. The superconducting
phase at the first band ϕ1 and that at the second band ϕ2 characterize a two-band superconducting state. We
consider a Josephson junction where an insulating barrier separates two such two-band ...

Added: October 8, 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

Demenev A. A., Grishina Y. V., Larionov A. V. et al., Physical Review B: Condensed Matter and Materials Physics 2017 Vol. 96 No. 15 P. 155308-1-155308-10

We address polarization instability in a freely decaying polariton condensate created by 2-ps-long linearly polarized laser pulses in the upper sublevel of the lower-polariton (LP) branch in a GaAs-based microcavity with reduced symmetry. The generated linearly polarized condensate is found to lose its stability at excitation densities above the threshold value: it passes into the ...

Added: February 15, 2018

Ziegler K., Sinner A., Yurii E. Lozovik, Physical Review Letters 2022 Vol. 128 No. 12 Article 157001

We consider s-wave pairing in a double layer of two chiral metals due to interlayer Coulomb interaction and study the Josephson effect near a domain wall, where the sign of the order parameter jumps. The domain wall creates two evanescent modes at the exceptional zero-energy point, whose superposition is associated with currents flowing in different ...

Added: May 9, 2022

Semenok D. V., Kvashnin А. G., Ivanova A. G. et al., Materials Today 2020 Vol. 33 P. 36-44

Here we report targeted high-pressure synthesis of two novel high-TC hydride superconductors, P63/mmc-ThH9 and Fm3m-ThH10, with the experimental critical temperatures (TC) of 146 K and 159–161 K and upper critical magnetic fields 38 and 45 Tesla at pressures 170–175 Gigapascals, respectively. Superconductivity was evidenced by the observation of zero resistance and a decrease of TC under external magnetic field ...

Added: November 26, 2019

Pudalov V., Kuzmicheva T. E., Kuzmichev S. A. et al., Physical Review B: Condensed Matter and Materials Physics 2018 Vol. 97 P. 235106-1-235106-10

We report on the Andreev spectroscopy and specific heat of high-quality single crystals of BaFe1.9Ni0.1As2.
The intrinsic multiple Andreev reflection spectroscopy reveals two anisotropic superconducting gaps L ≈
3.2−4.5 meV, S ≈ 1.2−1.6 meV (the ranges correspond to the minimum and maximum value of the coupling
energy in the kxky plane). The 25%−30% anisotropy shows the absence of ...

Added: August 4, 2018

Caruso R., Massarotti D., Bolginov V. V. et al., Journal of Applied Physics 2018 Vol. 123 No. 13 P. 133901-1-133901-6

We test the effect of an external RF field on the switching processes of magnetic Josephson junctions (MJJs) suitable for the realization of fast, scalable cryogenic memories compatible with Single Flux Quantum logic. We show that the combined application of microwaves and magnetic field pulses can improve the performances of the device, increasing the separation ...

Added: October 24, 2018

Glutsyuk A., Journal of Dynamical and Control Systems 2019 Vol. 25 No. 3 P. 323-349

In 1973, B. Josephson received a Nobel Prize for discovering a new fundamentaleffect concerning a Josephson junction,—a system of two superconductors separated by a very narrow dielectric: there could exist a supercurrent tunneling through this junction. We will discuss the model of the overdamped Josephson junction, which is given by a family of first-order nonlinear ...

Added: August 20, 2018

Bezuglyi E. V., Vasenko A. S., Shumeiko V. S. et al., Physical Review B: Condensed Matter and Materials Physics 2005 Vol. 72 No. 1 P. 014501-1-014501-12

We study nonequilibrium effects in current transport through voltage biased tunnel junction with long diffusive superconducting leads at low applied voltage eV << 2 Delta, and finite temperatures. Due to a small value of the Josephson frequency, the quasiparticle spectrum adiabatically follows the time evolution of the superconducting phase difference, which results in the formation ...

Added: November 29, 2017

Vasenko A. S., Golubov A. A., Kupriyanov M. Y. et al., Physical Review B: Condensed Matter and Materials Physics 2008 Vol. 77 No. 13 P. 134507-1-134507-9

We investigate superconductor/insulator/ferromagnet/superconductor tunnel Josephson junctions in the dirty limit using the quasiclassical theory. We formulate a quantitative model describing the oscillations of critical current as a function of thickness of the ferromagnetic layer and use this model to fit recent experimental data. We also calculate quantitatively the density of states (DOS) in this type ...

Added: November 29, 2017

Shapiro Dmitriy S., Mirlin A., Shnirman A., Physical Review B: Condensed Matter and Materials Physics 2018 Vol. 98 No. 24 P. 245405-1-245405-12

We consider a Josephson contact mediated by 1D chiral modes on a surface of a 3D topological insulator with superimposed superconducting and magnetic layers. The system represents an interferometer in which 1D chiral Majorana modes on the boundaries of superconducting electrodes are linked by ballistic chiral Dirac channels. This model may be realized also in ...

Added: February 7, 2019

М. : Московский государственный университет имени М.В. Ломоносова, Научно-исследовательский институт ядерной физики имени Д.В. Скобельцына, 2013

В трудах школы рассмотрены физические основы концентрированных потоков энергии и их воздействия на материалы и изделия космической техники, методы обработки материалов концентрированным излучением, воздействие лазерного и микроволнового излучения на вещество, концентрированные потоки энергии в экологии и медицине, в электронике, проблемы физики нейтрино и ядерной спектроскопии. ...

Added: November 28, 2013

O. O. Shvetsov, Esin V. D., Barash Y. S. et al., Physical Review B: Condensed Matter and Materials Physics 2020 Vol. 101 No. 3 P. 035304-1-035304-6

We experimentally study lateral electron transport between two 5−μm-spaced superconducting indium leads on a top of magnetic Weyl semimetal Co3Sn2S2. For the disordered magnetic state of Co3Sn2S2 crystal, we observe only the Andreev reflection in the proximity of each of the leads, which is indicative of highly transparent In-Co3Sn2S2 interfaces. If the sample is homogeneously magnetized, it demonstrates a well-developed ...

Added: December 1, 2020

Glutsyuk A., Filimonov D., Kleptsyn V. et al., / Cornell University. Series math "arxiv.org". 2013. No. 1301.7159.

In the present paper we investigate two-parametric family of nonautonomous ordinary differential equations on the two-torus that model the Josephson effect from superconductivity. We study its rotation number as a function of parameters and its Arnold tongues (also called phase locking domains): the level sets of the rotation number that have non-empty interior. The Arnold ...

Added: May 15, 2013

Pudalov V., Sadakov A., Vlasenko V. et al., The Journal of Physical Chemistry Letters 2023 Vol. 14 No. 29 P. 6666-6671

A comprehensive study of vortex phases and vortex dynamics is presented for a recently discovered high-temperature superconductor YH6 with Tc (onset) of 215 K under a pressure of 200 GPa. The thermal activation energy (U0) is derived within the framework of the thermally activated flux flow (TAFF) theory. The activation energy yields a power law dependence U0 ∝ Hα ...

Added: November 22, 2023

Шевчун А. Ф., Клинкова Л. А., Николайчик В. Н. et al., Физика металлов и металловедение 2018 Т. 119 № 3 С. 232-242

Методами рентгенофазового и химического анализов, электронной дифракции, элементного анализа
и высокого разрешения в просвечивающем электронном микроскопе исследованы состав и структу‑
ра керамических образцов оксида EuBa2Cu3O6+δ (Eu‑123), отожженных поэтапно в различных усло‑
виях – на воздухе, в атмосфере кислорода и аргона, при температуре 940–960 °С, в течение 1–70 ч
с использованием процедуры гомогенизации или без таковой. Продуктом отжига образцов, незави‑
симо от условий, является наноструктурированный оксид Eu‑123 с тетрагональной или ромбической
структурой ...

Added: February 26, 2020

Sadovskii M. V., Pudalov V.M., Journal of Superconductivity and Novel Magnetism 2016 Vol. 29 No. 4 P. 1035-1036

The conferences “Fundamental Problems of High Temperature Superconductivity” (FPS) have become traditional since the first one in 2004. The problem of high-temperature superconductivity remains highly topical: quite regularly, novel HTS materials come on stage (copper oxide high-Tc superconductors in 1986, magnesium diboride in 2001, iron pnictide and iron chalcogenide compounds in 2008, FeSe monolayers in ...

Added: February 23, 2017