The sensitive effect of ${\mathrm{O}}_2$ adsorption on the electronic properties of organic semiconductors is investigated by band structure calculation. ${\mathrm{O}}_2$ can actually $p$-dope the host materials even without illumination, i.e., a ground state property, in the circumstance of saturated coverage. Due to hybridization between ${\mathrm{O}}_2$ and polymer, Fermi level of the oxygenated system is pinned at the nearly half-filled oxygen band and overlap with host valence band. The doping depends critically on the ionization potential. Each ${\mathrm{O}}_2$ can dope more than 0.1 hole in dark and a full charge-transfer excitation around $2.3\mathrm{eV}$ photon energy is predicted.

Iridates represent a unique material system that possesses both strong spin-orbit coupling and electron correlation. The interplay between spin-orbit coupling and correlation could facilitate the emergence of novel electronic and magnetic states. In this work, we report on a systematic study of magnetism in the double perovskite iridate ${\mathrm{La}}_2{\mathrm{ZnIrO}}_6$ and its hole-doped compounds $\left({\mathrm{La}}_{1-x}{\mathrm{Sr}}_x\right){}_2{\mathrm{ZnIrO}}_6$ via dc magnetization measurement, heat capacity characterization, electron spin resonance spectroscopy, and simple modeling. Undoped ${\mathrm{La}}_2{\mathrm{ZnIrO}}_6$ undergoes two magnetic transitions, at $T_1\sim 7.3$ K and $T_2\sim 8.5$ K, respectively. While magnetic hysteresis loops with large remnant moments are observed below these two transition temperatures, the corresponding magnetic states are shown to be canted antiferromagnetic by the linear increase in magnetization in the high field region along with the observation of antiferromagnetic resonance. The nature of the canted antiferromagnetic states with large canting angles can be understood by a simple model that includes both the Heisenberg exchange interaction and the Dzyaloshinskii-Moriya interaction. With the introduction of ${\mathrm{Ir}}^{5+}$ by ${\mathrm{Sr}}^{2+}$ doping, the canted antiferromagnetic phases are suppressed, accompanied by an enhancement of electrical conductivity.

We consider a Josephson junction with an arbitrary transmission coefficient $\mathcal{D}$ between a singlet and a triplet superconductor with the latter order parameter characterized by a $d$ vector of the form $\left(k_x\widehat{y}-k_y\widehat{x}\right)$. Various quantities such as the tunneling current, spin accumulation, and spin current are calculated via the quasiclassical Green’s functions. We also present a symmetry argument on the existence of these quantities and their dependencies on the phase difference across the junction. A physical picture is also given in terms of the Andreev states near the junction.

We consider bound states at the vortex core of a non-centrosymmetric superconductor. We show that, despite the mixing of singlet and triplet order parameters, zero energy states survive within certain parameter space as in vortices of some chiral p-wave states.Comment: 5 pages, no figure Latest modification, an overall factor i is removed in eq. (4

We study theoretically the surface of time-reversal-symmetric, noncentrosymmetric superconductor with mixed singlet and triplet order parameters. A pair of counterpropagating subgap quasiparticle surface bound states with opposite spin projections are obtained in the nontrivial Z2 case where the triplet component is larger than the singlet one, contributing to a spin current with out-of-plane spin projection. In contrast to the pure p-wave cases, these subgap states do not have fixed spin projections, which, however, depend on the momenta along the surface. In the trivial Z2 case where the singlet order parameter is larger, no subgap surface bound states show up. In both cases, there is also a finite contribution to the spin current from the continuum states with energies between the two gaps. The method for obtaining the quasiclassical Green's functions associated with the noncentrosymmetric superconductors is also presented.