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## Multifractal correlations of the local density of states in dirty superconducting films

Physical Review Research. 2021. Vol. 3. Article L042016 .

Mesoscopic fluctuations of the local density of states encode multifractal correlations in disordered electron systems. We study fluctuations of the local density of states in a superconducting state of weakly disordered films. We perform numerical computations in the framework of the disordered attractive Hubbard model on two-dimensional square lattices. Our numerical results are explained by an analytical theory. The numerical data and the theory together form a coherent picture of multifractal correlations of local density of states in weakly disordered superconducting films.

Keywords: mesoscopic superconductivity

Publication based on the results of:

D.V. Averin, G. Wang, A.S. Vasenko, Physical Review B: Condensed Matter and Materials Physics 2020 Vol. 102 No. 14 P. 144516-1-144516-6

We extend the basic theory of Andreev reflection (AR) in a normal metal/superconductor junction to the situation with an arbitrary time-dependent bias voltage V(t) across the junction. The central element of the theory is the fact that the Fourier transform of the AR amplitude has a casual structure. As an example, the theory is used to describe ...

Added: October 13, 2020

Burmistrov I., Igor Gornyi, Alexander Mirlin, Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 93 P. 205432-1-205432-22

We develop a theory of the local density of states (LDOS) of disordered superconductors, employing the nonlinear sigma-model formalism and the renormalization-group framework. The theory takes into account the interplay of disorder and interaction couplings in all channels, treating the systems with short-range and Coulomb interactions on equal footing. We explore two-dimensional systems that would ...

Added: October 15, 2016

J. S. Lehtinen, Lvov B. G., Arutyunov K., Physics of the Solid State 2018 Vol. 60 No. 11 P. 2135-2138

Volt-ampere characteristics of narrow superconducting titanum wires have been studied experimentally. The narrowest specimens measured by means of high-resistance contacts have revealed a behavior nontrivial for superconductors: the Coulomb blockade. The Coulomb gap size correlates with the frequency of quantum phase slips. The observation confirms the identity of quantum dynamics of charge in the Josephson ...

Added: September 29, 2018

Arutyunov K., J. S. Lehtinen, A. A. Radkevich et al., Journal of Magnetism and Magnetic Materials 2018 Vol. 459 P. 356-358

Quasi-one-dimensional superconducting channels host sound-like plasma modes propagating along the
which are associated with fluctuations of the phase of the superconducting order parameter (Mooiji and
1985) [5]. Interaction between these electromagnetic excitations and charge carriers affects the electron density
of states (DOS). I-V characteristics of tunnel S1-I-S2 junctions, where superconducting S2 electrode
nanowire in the regime of quantum fluctuations ...

Added: October 1, 2017

Arutyunov K., M.: Lebedev Institute, 2017

Superconducting properties of metallic nanowires can be entirely different from those of bulk superconductors because of the dominating role played by thermal and quantum fluctuations of the order parameter. For superconducting channels with diameters below ∼ 50 nm fluctuations of the phase of the complex order parameter - the phase slippage - lead to non-zero ...

Added: October 1, 2017

P. A. Ioselevich, P. M. Ostrovsky, Ya. V. Fominov et al., Physical Review B: Condensed Matter and Materials Physics 2017 Vol. 95 No. 9 P. 094508-1-094508-6

We study Josephson junctions with weak links consisting of two parallel disordered arms with magnetic
properties: ferromagnetic, half-metallic, or normal with magnetic impurities. In the case of long links, the
Josephson effect is dominated by mesoscopic fluctuations. In this regime, the system realizes a phi_0 junction with
sample-specific phi_0 and critical current. Cooper pair splitting between the two ...

Added: October 18, 2017

D.V. Averin, G. Wang, Vasenko A.S., Time-dependent Andreev reflection / Cornell University. Series cond-mat "arxiv.org". 2020. No. 2007.07483.

We extend the basic theory of Andreev reflection (AR) in a normal metal/superconductor junction to the situation with an arbitrary time-dependent bias voltage V(t) across the junction. The central element of the theory is the fact that the Fourier transform of the AR amplitude has a casual structure. As an example, the theory is used to describe ...

Added: July 28, 2020

Ioselevich P., Chuklanov D. A., JETP Letters 2021 Vol. 113 P. 631-637

We consider a long diffusive Josephson junction where the weak link is a thin (normal metal (N)–ferromagnet (F)) bilayer (N and F form parallel links between superconductors (Ss)). We show that superconductivity in the weak link can be described by an effective one-dimensional Usadel equation containing a “diluted” exchange field as well as a weak ...

Added: October 25, 2021

Ioselevich P. A., P. M. Ostrovsky, Fominov Ya. V., Physical Review B: Condensed Matter and Materials Physics 2018 Vol. 98 P. 144521-1-144521-15

We study the supercurrent in quasi-one-dimensional Josephson junctions with a weak link involving magnetism, either via magnetic impurities or via ferromagnetism. In the case of weak links longer than the magnetic pair-breaking length, the Josephson effect is dominated by mesoscopic fluctuations. We establish the supercurrent-phase dependence I(ϕ) along with statistics of its sample-dependent properties in ...

Added: October 31, 2018

K. Yu. Arutyunov, J. S. Lehtinen, A. A. Radkevich et al., Physics of the Solid State 2017 Vol. 59 No. 11 P. 2110-2113

The current–voltage characteristics of superconductor–insulator–semiconductor (S1–I–S2)
tunnel junctions, where superconducting electrode S2 is a thin nanowire, are studied experimentally. The
observed blurring of the gap singularities is interpreted as a manifestation of the order parameter quantum
fluctuations. We propose a model taking into account the broadening of the density of states due to the interaction
of electrons with the ...

Added: November 29, 2017

Shein K., Zarudneva A., Emel’yanova V. et al., Physics of the Solid State 2020 Vol. 62 No. 9 P. 1539-1542

The transport properties of two types of quasi-one-dimensional superconducting microstructures were investigated at ultra-low temperatures: the narrow channels close-packed in the shape of meander, and the chains of tunneling contacts "superconductor-insulator-superconductor." Both types of the microstructures demonstrated high value of high-frequency impedance and-or the dynamic resistance. The study opens up potential for using of such ...

Added: September 18, 2020

Semenov A. G., Zaikin A., Physical Review B: Condensed Matter and Materials Physics 2019 Vol. 99 No. 9 P. 094516-1-094516-9

We work out a microscopic theory describing complete statistics of voltage fluctuations generated by quantum phase slips (QPS) in superconducting nanowires. We evaluate the cumulant generating function and demonstrate that shot noise of the voltage as well as the thir d and all higher voltage cumulants differ from zero only due to the presence of ...

Added: October 31, 2019

Ioselevich P., P.M. Ostrovsky, Fominov Y. et al., Cooper pair splitting in diffusive magnetic SQUIDs / Cornell University. Series "Working papers by Cornell University". 2016.

We study Josephson junctions with weak links consisting of two parallel disordered arms with magnetic properties -- ferromagnetic, half-metallic or normal with magnetic impurities. In the case of long links, the Josephson effect is dominated by mesoscopic fluctuations. In this regime, the system realises a $\varphi_0$ junction with sample-dependent $\varphi_0$ and critical current. Cooper pair ...

Added: October 15, 2016

P. L. Stroganov, Ya.V. Fominov, Physical Review B: Condensed Matter and Materials Physics 2017 Vol. 96 No. 17 P. 174508-1-174508-13

We consider ballistic SQUIDs with spin filtering inside half-metallic ferromagnetic arms. A singlet Cooper pair
cannot pass through an arm in this case, so the Josephson current is entirely due to the Cooper pair splitting, with
two electrons going to different interferometer arms. In order to elucidate the mechanisms of Josephson transport
due to split Cooper pairs, we ...

Added: November 17, 2017

П.А.Иоселевич, Чукланов Д. А., Письма в Журнал экспериментальной и теоретической физики 2021 Т. 113 № 10 С. 661-668

Рассматривается длинный диффузный контакт Джозефсона, слабой связью в котором является тонкий бислой нормальный металл (N)–ферромагнетик (F), так что N и F образуют параллельные связи между сверхпроводниками S. Показано, что сверхпроводимость в такой слабой связи описывается эффективным одномерным уравнением Узаделя, содержащим ослабленное обменное поле, а также распаривающий член. Механизм распаривания основан на неотъемлемой неоднородности бислоя и ...

Added: October 25, 2021

Alexey A. Radkevich, Semenov A. G., Zaikin A., European Physical Journal: Special Topics 2019 Vol. 227 No. 15-16 P. 2289-2295

We investigate the influence of quantum phase fluctuations on electron density of states (DOS) in ultrathin superconducting films and nanowires. Using an effective action approach we derive a non-perturbative correction to DOS in such systems. The main effect of phase fluctuations in quasi-two-dimensional films is the appearance of electron states at subgap energies while in ...

Added: October 28, 2019

Elo Temu, Pasi Lahteenmaki, Dmitry Golubev et al., Journal of Low Temperature Physics 2017 Vol. 189 P. 204-216

We have employed noise thermometry for investigations of thermal relaxation
between the electrons and the substrate in nanowires patterned from 40-nm-thick
titanium film on top of silicon wafers covered by a native oxide. By controlling the
electronic temperature Te by Joule heating at the base temperature of a dilution refrigerator,
we probe the electron–phonon coupling and the thermal boundary ...

Added: December 5, 2017

Dolgoprudni: [б.и.], 2016

Book of abstracts ...

Added: November 20, 2016

Shapiro D., Alexander Mirlin, Alexander Shnirman, Physical Review B: Condensed Matter and Materials Physics 2021 Vol. 104 No. 3 Article 035434

We consider an interferometer based on artificially induced topological superconductivity and chiral one-dimensional (1D) Majorana fermions. The (nontopological) superconducting island inducing the superconducting correlations in the topological substrate is assumed to be floating. This allows probing the physics of interfering Majorana modes via microwave response, i.e., the frequency-dependent impedance between the island and the earth. ...

Added: October 31, 2021

Shapiro Dmitriy S., Alexander D. Mirlin, Alexander Shnirman, 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

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

P. L. Stroganov, Ya. V. Fominov, Cooper pair splitting in ballistic ferromagnetic SQUIDs / Cornell University. Series cond-mat "arxiv.org". 2017. No. arXiv:1708.05089.

We consider ballistic SQUIDs with spin filtering inside half-metallic ferromagnetic arms. A singlet Cooper pair cannot pass through an arm in this case, so the Josephson current is entirely due to the Cooper pair splitting, with two electrons going to different interferometer arms. In order to elucidate the mechanisms of Josephson transport due to split ...

Added: October 18, 2017

Arutyunov K., J. S. Lehtinen, 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

Arutyunov K. Yu., S. A. Chernyaev, Karabassov T. et al., Journal of Physics: Condensed Matter 2018 Vol. 30 No. 343001 P. 1-16

Rapid development of micro- and nanofabrication methods have provoked interest
and enabled experimental studies of electronic properties of a vast class of (sub)micrometersize
solid state systems. Mesoscopic-size hybrid structures, containing superconducting
elements, have become interesting objects for basic research studies and various applications,
ranging from medical and astrophysical sensors to quantum computing. One of the
most important aspects of physics, ...

Added: July 31, 2018