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We theoretically investigate Josephson junctions with a phase shift of $\pi$ in various proximity induced one-dimensional superconductor models. One of the salient experimental signatures of topological superconductors, namely the…

Mesoscale and Nanoscale Physics · Physics 2015-09-28 Christian Spånslätt , Eddy Ardonne , Jan Carl Budich , Thors Hans Hansson

The phase and thermal driven transport properties of the T-shaped uncorrelated double quantum dot Josephson junction are analyzed by using Keldysh non-equilibrium Green's function equation of motion technique. In this setup, we have shown…

Mesoscale and Nanoscale Physics · Physics 2023-03-10 Bhupendra Kumar , Sachin Verma , Ajay

Topological features of low dimensional superconductors have caused a lot of excitement recently because of their broad range of applications in quantum information and their potential to reveal novel phases of quantum matter. A potential…

Superconductivity · Physics 2015-06-18 Paul Matthews , Pedro Ribeiro , Antonio M. García-García

We use a hybrid superconductor-semiconductor transmon device to perform spectroscopy of a quantum dot Josephson junction tuned to be in a spin-1/2 ground state with an unpaired quasiparticle. Due to spin-orbit coupling, we resolve two…

We study the effect of a magnetic field on the current-phase relation of a topological Josephson junction formed by connecting two superconductors through the helical edge states of a quantum spin-Hall insulator. We predict that the Zeeman…

Mesoscale and Nanoscale Physics · Physics 2015-07-27 Fabrizio Dolcini , Manuel Houzet , Julia S. Meyer

Two superconductors coupled by a weak link support an equilibrium Josephson electrical current which depends on the phase difference $\varphi$ between the superconducting condensates [1]. Yet, when a temperature gradient is imposed across…

Mesoscale and Nanoscale Physics · Physics 2017-05-25 Antonio Fornieri , Giuliano Timossi , Pauli Virtanen , Paolo Solinas , Francesco Giazotto

Josephson currents are carried by sharp Andreev states within the superconducting energy gap. We theoretically study the electronic transport of a magnetically tunable nanoscale junction consisting of a quantum dot connected to two…

Mesoscale and Nanoscale Physics · Physics 2014-04-11 P. Stadler , C. Holmqvist , W. Belzig

We study Josephson junctions based on second-order topological superconductors (SOTSs) which can be realized in quantum spin Hall insulators with large inverted gap in proximity to unconventional superconductors. We find that tuning the…

Superconductivity · Physics 2020-01-22 Song-Bo Zhang , Björn Trauzettel

We investigate the Josephson transport properties in a Josephson junction consisting of a conventional $s$-wave superconductor coupled to a multi-orbital noncentrosymmetric superconductor marked by an orbitally driven inversion asymmetry…

Superconductivity · Physics 2020-10-21 Yuri Fukaya , Yada Keiji , Yukio Tanaka , Paola Gentile , Mario Cuoco

In this work we investigate the supercurrent in a hybrid topological Josephson junction consisting of two planes of topological insulator (TI) in a specific configuration, which allows both local (LAR) and crossed (CAR) Andreev processes at…

Mesoscale and Nanoscale Physics · Physics 2019-03-06 Gianmichele Blasi , Fabio Taddei , Vittorio Giovannetti , Alessandro Braggio

Superconducting quantum circuits derive their nonlinearity from the Josephson energy-phase relation. Besides the fundamental $\cos\phi$ term, this relation can also contain higher Fourier harmonics $\cos(k\phi)$ corresponding to correlated…

The transport properties of a topological Josephson junction fabricated from a magnetically doped topological insulator (TI) were investigated. The conductance spectra of the Nb/Fe-Bi$_2$Te$_2$Se/Nb junction below 1 K showed an unusual…

We study junctions between superconductors mediated by the edge states of a quantum spin Hall insulator. We show that such junctions exhibit a fractional Josephson effect, in which the current phase relation has a 4\pi, rather than a 2\pi…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Liang Fu , C. L. Kane

We consider an interacting quantum dot strongly coupled to two superconducting leads in a Josephson junction geometry. By defining symmetry-adapted superpositions of states from the leads, we formulate an effective Hamiltonian for the…

Mesoscale and Nanoscale Physics · Physics 2024-01-17 Luka Pavešič , Ramón Aguado , Rok Žitko

We consider a model of a Josephson junction of two topological superconducting wires mediated by an interacting quantum dot. An additional normal electrode coupled to the dot from the top allows to probe its density of states. The Majorana…

Mesoscale and Nanoscale Physics · Physics 2019-03-07 Piotr Stefański

Time reversal invariant topological superconducting (TRITOPS) wires are known to host a fractional spin hbar/4 at their ends. We investigate how this fractional spin affects the Josephson current in a TRITOPS-quantum dot-TRITOPS Josephson…

Mesoscale and Nanoscale Physics · Physics 2017-08-02 Alberto Camjayi , Liliana Arrachea , Armando Aligia , Felix von Oppen

We study a junction between two time-reversal-invariant topological superconductors and show this system goes through a series of multiple transitions between a $0$-junction phase, where the free energy has its minimum for a superconducting…

Mesoscale and Nanoscale Physics · Physics 2019-11-01 Arbel Haim

We investigate the supercurrent through a quantum dot for the whole range of couplings using the numerical renormalization group method. We find that the Josephson current switches abruptly from a $\pi$- to a 0-phase as the coupling…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Mahn-Soo Choi , Minchul Lee , Kicheon Kang , W. Belzig

Bound states in quantum dots coupled to superconductors can be in a coherent superposition of states with different electron number but with the same fermion parity. Electrostatic gating can tune this superposition to a sweet spot, where…

Mesoscale and Nanoscale Physics · Physics 2024-06-18 Max Geier , Rubén Seoane Souto , Jens Schulenborg , Serwan Asaad , Martin Leijnse , Karsten Flensberg

Supercurrent transport is experimentally studied in a Josephson junction hosting a double quantum dot (DQD) with tunable symmetries. The QDs are parallel-coupled to two superconducting contacts and can be tuned between strong inter-dot…

Mesoscale and Nanoscale Physics · Physics 2022-12-14 Rousan Debbarma , Markus Aspegren , Florinda Viñas Boström , Sebastian Lehmann , Kimberly Dick , Claes Thelander