Related papers: Van Hove Singularity and Superconductivity in Diso…
We examine the effects of a van Hove singularity (vHs) in the density of states (DOS) of a two dimensional, $t-t'-U$ Hubbard model within the local approximation. Within our approximation the non-interacting Fermi surface is always retained…
We investigate the effect of white-noise disorder on the local phase stiffness and thermodynamic properties of a two-dimensional $s$-wave superconductor. Starting from a local attractive model and using path-integral formalism, we derive an…
The effects of planar hole concentration, p, and in-plane disorder, Zn (y), on the DC resistivity, r(T), of sintered samples of Y_{1-x}Ca_xBa_2(Cu_{1-y}Zn_y)_3O_{7-d} were investigated over a wide doping range by changing both the oxygen…
Magnetic impurities in a superconductor induce Yu-Shiba-Rusinov (YSR) states inside the superconducting gap, whose energy depends on the strength of the coupling to the impurity and on the density of states (DOS) at the Fermi level. We…
Sr$_{2}$RuO$_{4}$ (SRO) is the prime candidate for chiral $p$-wave superconductor with critical temperature $T_{c}(SRO)\sim$1.5 K. Chiral domains with opposite chiralities $p_{x}\pm ip_{y}$ were proposed, but yet to be confirmed. We measure…
The effect of disorder on the superconducting transition temperature $T_{c}$ of cuprate superconductors is examined. Disorder is introduced into the cation sites in the plane adjacent to the CuO$_{2}$ planes of two single-layer systems,…
Sr$_2$RuO$_4$ is a leading candidate for chiral $p$-wave superconductivity. The detailed mechanism of superconductivity in this material is still the subject of intense investigations. Since superconductivity is sensitive to the topology of…
We use functional renormalization group method to study a three-orbital model for superconducting Sr$_2$RuO$_4$. Although the pairing symmetry is found to be chiral $p$-wave, the atomic spin-orbit coupling induces near-nodes for…
We use a novel temperature-flow renormalization group technique to analyze magnetic and superconducting instabilities in the two-dimensional t-t' Hubbard model for particle densities close to the van Hove filling as a function of the…
We use a diagrammatic approach to study low energy physics of a two dimensional electron system where the Fermi level is near van-Hove singularies in the energy spectrum. We find that in most regions of the $\epsilon_F-T$ phase diagram the…
Chemical substitution is a promising route for the exploration of a rich variety of doping- and/or disorder-dependent collective phenomena in low-dimensional quantum materials. Here we show that transition metal dichalcogenide alloys are…
Motivated by the sensitivity of Sr$_2$RuO$_4$ to Fermi surface reconstructions under strain, we investigate how Fermi surface geometry and Van Hove singularities influence the optical Hall response and polar Kerr effect. Within a…
We present a theory for the van Hove singularity (VHS) in the tunneling density of states (TDOS) of disordered multichannel quantum wires, in particular multi-wall carbon nanotubes. We assume close-by gates which screen off…
Hole-doped cuprate superconductors show a ubiquitous tendency towards charge order. Although onset of superconductivity is known to suppress charge order, there has not so far been a decisive demonstration of the reverse process, namely,…
Influence of weak nonmagnetic impurities on the single-particle density of states $\rho(\omega)$ of two-dimensional electron systems with a conical spectrum is studied. We use a nonperturbative approach, based on replica trick with…
The finite temperature phase diagram for the 2D attractive fermion Hubbard model with spin-dependent disorder is considered within Bogoliubov-de Gennes mean field theory. Three types of disorder are studied. In the first, only one species…
We study the critical behavior driven by potential quantum critical points (QCPs) termed as $\tau_{0,x,y,z}$-Type QCPs in the $d$-wave cuprate superconductors. Within the framework of the renormalization group approach, we construct the…
We present results from point-contact measurements on Sr$_2$RuO$_4$ that show a linear dependence of the excess current as a function of temperature and applied magnetic fields over a surprisingly wide range of the phase diagram. We propose…
We present a study of the electronic ultrasound attenuation $\alpha$ in the unconventional superconductor Sr$_2$RuO$_4$ . The power law behavior of $\alpha$ at temperatures down to $T_c/30$ clearly indicates the presence of nodes in the…
We study the evolution of temperature-dependent resistivity with controlled point-like disorder induced by 2.5 MeV electron irradiation in stoichiometric compositions of the "3-4-13" stannides,…