Layered singlet paired superconductors with disorder and broken time reversal symmetry are studied, demonstrating a phase diagram with charge-spin separation in transport. In terms of the average intergrain transmission and the interlayer tunneling we find quantum Hall phases with spin Hall coefficients of sigma(spin)(xy)=0,2 separated by a spin metal phase. We identify a spin metal-insulator l...

We consider 3D active plane rotators, where the interaction between the spins is of XY-type and where each spin is driven to rotate. For the clock-model, when the spins take N 1 possible values, we conjecture that there are two low-temperature regimes. At very low temperatures and for small enough drift the phase diagram is a small perturbation of the equilibrium case. At larger temperatures th...

It is well known that the 2D XY model exhibits an unusual infinite order phase transition belonging to the Kosterlitz-Thouless (KT) universality class. Introduction of a nematic coupling into the XY Hamiltonian leads to an additional phase transition in the Ising universality class [D. H. Lee and G. Grinstein, Phys. Rev. Lett. 55, 541 (1985)]. Using a combination of extensive Monte Carlo simula...

We investigate the stability of the square vortex lattice which has been recently observed in experiments on the borocarbide family of superconductors. Taking into account the tetragonal symmetry of these systems, we add fourfold symmetric fourth-derivative terms to the Ginzburg-Landau(GL) free energy. At Hc2 these terms may be treated perturbatively to lowest order to locate the transition fro...

Layered singlet paired superconductors with disorder and broken time reversal symmetry are studied focusing on edge states and the corresponding quantum Hall effects. We find quantum Hall phases with spin Hall coefficients of σ xy = 0, 2 separated by a spin metal phase. We identify a spin metal-insulator localization exponent as well as a spin conductivity exponent of ≈ 0.96. In presence of a Z...

We consider Green's functions $G(z):=(H-z)^{-1}$ of Hermitian random band matrices $H$ on the $d$-dimensional lattice $(\mathbb Z/L\mathbb Z)^d$. The entries $h_{xy}=\bar h_{yx}$ are independent centered complex Gaussian variables with variances $s_{xy}=\mathbb E|h_{xy}|^2$. satisfy a banded profile so that $s_{xy}$ is negligible if $|x-y|$ exceeds width $W$. For any $n\in \mathbb N$, we constr...

Magnetic transition element doping in topological insulators, which breaks the time-reversal symmetry, gives rise to diverse range of exotic consequences, though proper understanding magnetic order has rarely been attempted by using any microscopic experiments. We report occurrence (${\mathrm{Sb}}_{0.95}{\mathrm{Cr}}_{0.05}{)}_{2}{\mathrm{Te}}_{3}$ muon spin relaxation studies. The asymmetry cu...

Magnetic transition element doping in topological insulators, which breaks the time-reversal symmetry, gives rise to diverse range of exotic consequences, though proper understanding magnetic order has rarely been attempted by using any microscopic experiments. We report occurrence (${\mathrm{Sb}}_{0.95}{\mathrm{Cr}}_{0.05}{)}_{2}{\mathrm{Te}}_{3}$ muon spin relaxation studies. The asymmetry cu...

We study the phase transitions of a restricted solid-on-solid model coupled to an Ising model, which can be derived from the coupled XY-Ising model. There are two kinds of phase transition lines. One is a Ising transition line and the other is surface roughening transition line. The latter is a KT transition line from the viewpoint of the XY model. Using a microcanonical Monte Carlo technique, ...

We study an asymptotic behavior of the probability of formation of a ferromagnetic string (referred to as EFP) of length n in a ground state of the one-dimensional anisotropic XY model in a transversal magnetic field as n → ∞. We find that it is exponential everywhere in the phase diagram of the XY model except at the critical lines where the spectrum is gapless. One of those lines corresponds ...