Coexistence and tuning of spin-singlet and triplet transport in spin-filter Josephson junctions

Abstract

The increased capabilities of coupling more and more materials through functional interfaces are paving the way to a series of exciting experiments and extremely advanced devices. Here we focus on the capability of magnetically inhomogeneous superconductor/ferromagnet (S/F) interfaces to generate spin-polarized triplet pairs. We build on previous achievements on spin-filter ferromagnetic Josephson junctions (JJs) and find direct correspondence between neat experimental benchmarks in the temperature behavior of the critical current and theoretical modelling based on microscopic calculations, which allow to determine a posteriori spin-singlet and triplet correlation functions. This kind of combined analysis provides an accurate proof of the coexistence and tunability of singlet and triplet transport. This turns to be a powerful way to model disorder and spin-mixing effects in a JJ to enlarge the space of parameters, which regulate the phenomenology of the Josephson effect and could be applied to a variety of hybrid JJs.

Anomalous Josephson coupling and high-harmonics in non-centrosymmetric superconductors with S-wave spin-triplet pairing

“…Observations of CPR in form of φ 0 or φ-junctions as well as 0-π transitions have been reported in a variety of devices based on InSb nanowires 29 , ferromagnetic heterostructures 23,30 , superconducting spin valves 31,32 , and junctions with superconducting materials having non-trivial gap symmetry (e.g., iron picnitides 33 , oxides interface 34,35 , and cuprates 25,26,36 ). Here, competing 0-and π-Josephson channels lead to a vanishing first harmonic with a consequent dominant role of the second harmonic in determining the Josephson CPR.…”

Microwave spectroscopy of interacting Andreev spins

“…The experimental detection has, however, proven more challenging. Early signatures of triplet supercurrent have been reported in Josephson junctions with magnetic materials [30][31][32][33] and more recently in experiments making use of materials with spin-orbit coupling to induce spin mixing [34][35][36][37]. In hybrid semiconductorsuperconductor systems, a precursor of triplet pairing stems from the observation of the anomalous Josephson effect in InAs/Al nanowires [38,39] and in two-dimensional electron gases (2DEGs) [40].…”

Autonomous piecewise damping Josephson junction jerk oscillator: microcontroller implementation, controls, and combination synchronization

“…The violation of the classical standpoint by this phenomenon (conduction of electrons through blockade namely insulators or vacuum) has interestingly shifted concern to the domain [13,14]. Intense nonlinear considerations have subjected the junction to novel applications and technologies which are but not limited to metrology measurements [15,16], digital logic cryogenic [17], magnetometers [18,19], parametric amplifiers [20,21], spin-filters [22,23], voltage standards [24,25], highly responsive SQUID sensors [26,27], mechanical actuators [28,29], encryption [30], generation of random numbers [31,32], and microwave detectors [33].…”