Gábor B. Halász

Time-reversal invariant realization of the Weyl semimetal phase

We propose a realization of the Weyl semimetal phase that is invariant under time reversal and occurs due to broken inversion symmetry. We consider both a simple superlattice model and a more realistic tight-binding model describing an experimentally reasonable HgTe/CdTe multilayer structure. The two models have the same underlying symmetry, therefore their low-energy features are equivalent. We find a Weyl semimetal phase between the normal insulator and the topological insulator phases that exists for a finite range of the system parameters and exhibits a finite number of Weyl points with robust band touching at the Fermi level. This phase is experimentally characterized by a strong conductivity anisotropy and topological surface states. The principal conductivities change in a complementary fashion as the system parameters are varied, and the surface states only exist in a region of momentum space that is determined by the positions of the Weyl points.

Critical current of a Josephson junction containing a conical magnet

We calculate the critical current of a superconductor/ferromagnetic/superconductor (S/FM/S) Josephson junction in which the FM layer has a conical magnetic structure composed of an in-plane rotating antiferromagnetic phase and an out-of-plane ferromagnetic component. In view of the realistic electronic properties and magnetic structures that can be formed when conical magnets such as Ho are grown with a polycrystalline structure in thin-film form by methods such as direct current sputtering and evaporation, we have modeled this situation in the dirty limit with a large magnetic coherence length (

Magnetic-coupling-dependent spin-triplet supercurrents in helimagnet/ferromagnet Josephson junctions

\xi_f

Fracton Topological Phases from Strongly Coupled Spin Chains

). This means that the electron mean free path is much smaller than the normalized spiral length

Supercurrent enhancement in Bloch domain walls

\lambda/2\pi

Topological Rényi entropy after a quantum quench.

which in turn is much smaller than

Supra-oscillatory critical temperature dependence of Nb-Ho bilayers

\xi_f

Universality and robustness of revivals in the transverse field X Y model

(with

Probing spinon nodal structures in three-dimensional kitaev spin liquids

\lambda

All Majorana Models with Translation Symmetry are Supersymmetric

as the length a complete spiral makes along the growth direction of the FM). In this physically reasonable limit we have employed the linearized Usadel equations: we find that the triplet correlations are short ranged and manifested in the critical current as a rapid oscillation on the scale of