Isospin magnetism and spin-polarized superconductivity in Bernal bilayer graphene

In conventional superconductors, Cooper pairing occurs between electrons of opposite spin. We observe spin-polarized superconductivity in Bernal bilayer graphene when doped to a saddle-point van Hove singularity generated by large applied perpendicular electric field. We observe a cascade of electrostatic gate-tuned transitions between electronic phases distinguished by their polarization within the isospin space defined by the combination of the spin and momentum-space valley degrees of freedom. Although all of these phases are metallic at zero magnetic field, we observe a transition to a superconducting state at finite B ‖ ≈ 150mT applied parallel to the two-dimensional sheet. Superconductivity occurs near a symmetry breaking transition, and exists exclusively above the B ‖ -limit expected of a paramagnetic superconductor with the observed transition temperature T C ≈ 30mK, consistent with a spin-triplet order parameter.

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

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.

Impact of Dopant-induced Ensemble Structure of Hetero Double Atom Catalysts in Electrochemical NH3 Production

Using the spin-polarized density functional theory (DFT) calculations, we examined the electrochemical N2 reduction (N2RR) toward NH3 production on the hetero RuM (M = 3d transition metals) double atom catalysts...

Robust Dirac spin gapless semiconductors in a two-dimensional oxalate based organic Honeycomb-Kagome lattice

Two-dimensional (2D) ferromagnetic materials with intrinsic and robust spin-polarized Dirac cone are of great interest to explore exciting physics and to realize spintronic devices. Using comprehensive ab initio calculations, herein...

Computational design of double transition metal MXenes with intrinsic magnetic properties

Two-dimensional transition metal carbides (MXenes) have a great potential to achieve intrinsic magnetism due to their available chemical and structural diversity. In this work, by spin-polarized density functional theory calculations,...