相关论文: RVB Contribution to Superconductivity in $MgB_2$
The structural, transport and magnetic properties of MgB2 superconductor heavily blended with Mg is studied. The samples are synthesized with a new approach in both, pressed carbon environment and in flowing argon. The excess magnesium used…
The study of the anisotropic superconductor MgB2 using a combination of scanning tunneling microscopy and spectroscopy reveals two distinct energy gaps at Delta1=2.3 meV and Delta2=7.1 meV. Different spectral weights of the partial…
Starting from first principles, we show the formation and evolution of superconducting gaps in MgB$_2$ at its ultrathin limit. Atomically thin MgB$_2$ is distinctly different from bulk MgB$_2$ in that surface states become comparable in…
The Rashba superconductor, in which spin-splitting bands become superconducting, is fascinating as a novel superconducting system in low dimensional systems. Here, we present the results of $\textit{in-situ}$ transport measurements on a…
Boron in MgB_2 forms layers of honeycomb lattices with magnesium as a space filler. Band structure calculations indicate that Mg is substantially ionized, and the bands at the Fermi level derive mainly from B orbitals. Strong bonding with…
We present a Ginzburg-Landau formulation of the bosonic resonating valence bond (RVB) theory of superconductivity. The superconducting order parameter is characterized by phase vortices that describe spinon excitations and the transition to…
Far-infrared reflectivity studies on the polycrystalline intermetallic compound MgB_2 with a superconducting transition temperature T_c=39 K were performed at temperatures 20 K to 300 K. We observe a significant raise of the…
The superconducting diode effect may exist in bulk systems as well as in junctions when time-reversal and inversion symmetries are simultaneously broken. Magnetization gradients and textures satisfy both requirements and therefore also…
We present measurements and simulations of superconducting Nb co-planar waveguide resonators on sapphire substrate down to millikelvin temperature range with different readout powers. In the high temperature regime, we demonstrate that the…
Graphene is at the forefront of condensed matter sciences, because of a variety of interesting phenomena it supports. If graphene could support high Tc superconductivity, after doping for example, it will make it even more valuable. Some…
Graphene nanoribbons support a range of electronic phases that can be controlled via external stimuli. Zigzag-edged graphene nanoribbons (ZGNRs), in particular, exhibit an antiferromagnetic insulating ground state that transitions to a…
The magnetic properties of a quasi two-dimensional superconductor, Sn-metal graphite (MG), are studied using DC and AC magnetic susceptibility. Sn-MG has a unique layered structure where Sn metal layer is sandwiched between adjacent…
We construct a family of simple fermionic projected entangled pair states (fPEPS) on the square lattice with bond dimension $D=3$ which are exactly hole-doped resonating valence bond (RVB) wavefunctions with short-range singlet bonds. Under…
Combining mean-field and renormalization group analyses, here we unveil the nature of recently observed superconductivity and parent metallic states in chemically doped rhombohedral trilayer graphene, subject to external electric…
We report resistivity and magnetization of single crystal MgB2, focusing on the broadening of superconducting (SC) transition in magnetic fields. In-plane and out-of-plane resistivity indicate that the broadening of superconducting…
According to the crystal structure of MgB$_{2}$ and band structure calculations quasi-two-dimensional (2D) boron planes are responsible for the superconductivity. We report on critical fields and resistance measurements of 30 nm thick…
The contribution of bulk and surface to the electrical resistance along crystallographic \textit{b}- and \textit{c}-axes as a function of crystal thickness gives evidence for a temperature independent surface states in an antiferromagnetic…
We have studied the structure of the superconducting gap in MgB2 thin films by means of point-contact spectroscopy using a gold tip. The films were produced by depositing pure boron on a sapphire substrate, using e-beam evaporation,…
We theoretically study a possible topological superconductivity in the interacting two layers of Rashba systems, which can be fabricated by the hetero-structures of semiconductors and oxides. The hybridization, which induces the gap in the…
Recently it was shown that vacuum in a background of strong enough magnetic field becomes an electromagnetic superconductor due to interplay between strong and electromagnetic forces. The superconducting ground state of the vacuum is…