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Temporal universal conductance fluctuations (TUCF) are observed in RuO$_2$ nanowires at cryogenic temperatures. The fluctuations persist up to very high $T \sim 10$ K. Their root-mean-square magnitudes increase with decreasing $T$, reaching…

Mesoscale and Nanoscale Physics · Physics 2011-10-18 An-Shao Lien , L. Y. Wang , C. S. Chu , Juhn-Jong Lin

We develop a concise self-consistent perturbation expansion for superconductivity where all the pair processes are naturally incorporated without drawing "anomalous" Feynman diagrams. This simplification results from introducing an…

Superconductivity · Physics 2011-11-16 Takafumi Kita

Density-wave instabilities have been observed and studied in a multitude of materials. Most recently, in the context of unconventional superconductors like the iron-based superconductors, they have excited considerable interest. We analyze…

Strongly Correlated Electrons · Physics 2018-08-31 Mareike Hoyer , Jörg Schmalian

We report on measurements of the magnetoconductance of an open circular InGaAs quantum dot between 1.3K and 204K. We observe two types of magnetoconductance fluctuations: universal conductance fluctuations (UCFs), and 'focusing'…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 B. Hackens , S. Faniel , F. Delfosse , C. Gustin , H. Boutry , I. Huynen , X. Wallaert , S. Bollaert , A. Cappy , V. Bayot

Conductions fluctuations (CF) are studied in single layer graphene devices with superconducting source and drain contacts made from aluminium. The CF are found to be enhanced by superconductivity by a factor of 1.4 to 2. This (near)…

Mesoscale and Nanoscale Physics · Physics 2011-09-19 F. Freitag , J. Trbovic , C. Schönenberger

In the vicinity of a phase transition, the order parameter starts fluctuating before vanishing at the critical point. The fluctuation regime, i.e. the way the ordered phase disappears, is a characteristics of a transition, and determines…

A strong mutual influence of superconductors (S) and ferromagnetic (F) conductors in hybrid F/S (Ni/Al) nanostructures is observed. The magnitude of a proximity-induced conductance on the F-side is more than two orders larger than that…

Superconductivity · Physics 2009-10-31 V. T. Petrashov , I. A. Sosnin , I. Cox , A. Parsons , C. Troadec

We present a truly canonical theory of superconductivity in ultrasmall metallic grains by variationally optimizing fixed-N projected BCS wave-functions, which yields the first full description of the entire crossover from the bulk BCS…

Superconductivity · Physics 2009-10-31 Fabian Braun , Jan von Delft

Motivated by a recent experimental observation of superconductivity in the Al-Zn-Mg quasicrystal, we study the low-temperature behavior of electrons moving in the quasiperiodic potential of the Ammann-Beenker tiling in the presence of a…

Superconductivity · Physics 2019-07-12 Ronaldo N. Araújo , Eric C. Andrade

In this letter, we investigate the fluctuation effects on the transport properties of unitary Fermi gases in the vicinity of the superfluid transition temperature $T_c$. Based on the time-dependent Ginzburg-Landau formalism of the BEC-BCS…

Quantum Gases · Physics 2014-12-17 Boyang Liu , Hui Zhai , Shizhong Zhang

We report low-temperature magnetoconductance measurements of a patterned two-dimensional electron system (2DES) at the surface of strontium titanate, gated by an ionic liquid electrolyte. We observe universal conductance fluctuations, a…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 Sam W. Stanwyck , P. Gallagher , J. R. Williams , David Goldhaber-Gordon

We report a novel phenomenon that the universal conductance fluctuations (UCF) can be suppressed by a small electric field E. The experiment has been carried out on single crystals of Si doped heavily with P and B beyond the critical…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Arindam Ghosh , A. K. Raychaudhuri

We consider a clean layered magnetic superconductor in which a continuous magnetic transition takes place inside superconducting state and the exchange interaction between superconducting and magnetic subsystems is weak so that…

Superconductivity · Physics 2020-08-10 A. E. Koshelev

Recently an N=1 supersymmetric model of BCS superconductivity was proposed realizing spontaneous symmetry breaking of a U(1)_R symmetry. Due to scalar contributions the superconducting phase transition turned out to be first order rather…

High Energy Physics - Theory · Physics 2015-06-12 Alejandro Barranco

A key feature of topological insulators (TI) is symplectic symmetry of the Hamiltonian which changes to unitary when time reversal symmetry is lifted and the topological phase transition occurs. However, such a crossover has never been…

Mesoscale and Nanoscale Physics · Physics 2018-09-21 Saurav Islam , Semonti Bhattacharyya , Hariharan Nhalil , Suja Elizabeth , Arindam Ghosh

We report an unconventional and promising route to self-assemble distributed superconductor-ferromagnet-superconductor (S-F-S) Josephson Junctions on single crystal [100] MgO. These structures consist of [110] epitaxial nano-plaquettes of…

Superconductivity · Physics 2009-07-31 S. K. Bose , R. C. Budhani

We study anomalous mesoscopic transport effects at the onset of the superconducting transition focusing on the observed large Nernst-Ettinghausen signal in disordered thin films. In the vicinity of the transition, as the Ginzburg-Landau…

Superconductivity · Physics 2019-05-15 Mengling Hettinger , Maxim Khodas , Alex Levchenko

Using a scattering matrix approach and quasiclassical Green's function technique, we calculate the conductance of the S/N system (see Fig.1). We establish that the difference between the superconducting and normal state conductance $(\delta…

Superconductivity · Physics 2019-08-17 C. J. Lambert , R. Seviour , A. F. Volkov

The exchange interaction at interfaces between superconductors (SCs) and ferromagnets (FMs) has been a central topic in condensed matter physics for many decades, starting with the prediction of exotic phases such as the…

Superconductivity · Physics 2025-12-09 Tao Yu , Xi-Han Zhou , Gerrit E. W. Bauer , Irina Bobkova

We calculate the contribution of superconducting fluctuations to thermal transport in the normal state, for low magnetic fields. We do so in the Gaussian approximation to their critical dynamics which is also the Aslamazov-Larkin…

Superconductivity · Physics 2009-11-07 Iddo Ussishkin , S. L. Sondhi , David A. Huse