Properties of the zero energy Andreev bound state in a two sublattice SNS junction

We study properties of the zero energy Andreev bound state in a superconductor-normal metal-superconductor(SNS) junction consisting of two intrinsic degrees of freedom. The superconductors on either sides of the normal metal are assumed to have two sublattices with an $intra$-sublattice pairing with a phase of zero or $\pi$ between the two sublattices. In addition, we add a uniform $inter$-sublattice pairing and study its effect on the local density of states (LDOS). In particular, we find that as the inter-sublattice pairing is turned on, the zero bias peak (ZBP) is unstable (robust) when the phase difference across the sublattices is $\pi$ (zero). We discuss the relevance of our results to the recently proposed odd parity $-\eta$ pairing ground states in Iron based superconductors (FeSCs).Comment: 8 pages, 5 figures. Modified version accepted in EP

Pressure Effects on Magnetically-Driven Electronic Nematic States in Iron-Pnictides

In a magnetically driven electronic nematic state, an externally applied uniaxial strain rounds the nematic transition and increases the magnetic transition temperature. We study both effects in a simple classical model of the iron-pnictides expressed in terms of local SO(N) spins (with N = 3) which we solve to leading order in 1=N. The magnetic transition temperature is shown to increase linearly in response to an external strain while a sharp crossover, which is a remnant of the nematic transition, can only be identified for extremely small strain. We show that these results can reasonably account for recent neutron experimental data in BaFe2As2 by C. Dhital et al [1].Comment: 4 pages and 4 figure