Related papers: Large mass enhancement in RbOs2O6
We report the discovery of a new pyrochlore oxide superconductor RbOs2O6. The compound crystallizes in the same beta-pyrochlore structure as the recently discovered superconductor KOs2O6, where Os atoms form a corner-sharing tetrahedral…
Measurements of the specific heat of Mg ^{11}B_2 (MgB2), from 1 to 50 K, in magnetic fields to 9 T, give the Debye temperature, $\Theta$ = 1050 K, the coefficient of the normal-state electron contribution, $\gamma_n$ = 2.6 mJ mol^{-1}…
The electronic structure and thermopower ($\alpha$) behavior of LaFeO$_{3}$ compound were investigated by combining the ab-initio electronic structures and Boltzmann transport calculations. LSDA plus Hubbard U (U = 5 eV) calculation on…
It is argued that the origin of the buckling of the CuO$_{2}$ planes in certain cuprates as well as the strong electron-phonon coupling of the $B_{1g}$ phonon is due to the electric field across the planes induced by atoms with different…
The optical reflectivity of Pb$_{0.865}$Sn$_{0.135}$Se and Pb$_{0.75}$Sn$_{0.25}$Se solid solutions was measured in the THz spectral region energetically corresponding to bulk optical phonon excitations and in the temperature range from 40…
We reassess the validity of Migdal-Eliashberg (ME) theory for coupled electron-phonon systems for large couplings $\lambda$. Although model calculations have found that ME theory breaks down for $\lambda\sim 0.5$, it is routinely applied…
Neutron resonance spin-echo spectroscopy was used to monitor the temperature evolution of the linewidths of transverse acoustic phonons in lead across the superconducting transition temperature, $T_c$, over an extended range of the…
Pursuing higher-temperature superconductors under ambient pressure continues to be a prominent topic in materials discovery. Isomorphic structures like MgB2 exhibit potential for conventional BCS-type superconductivity, but their transition…
Electron-boson coupling plays a key role in superconductivity for many systems. However, in copper-based high-temperature ($T_c$) superconductors, its relation to superconductivity remains controversial despite strong spectroscopic…
Searching for ambient-pressure conventional superconductors with critical temperatures (TC) higher than 40 K is a key challenge in the field of high-temperature superconductivity, mainly due to lack of efficient and effective models to…
Specific heat and resistivity measurements were performed on polycrystalline samples of the solid-solution Y_xLu_(1-x)Ni2B2C in order to determine thermodynamic properties such as the specific-heat difference, the thermodynamic critical…
We report magnetization measurements under high hydrostatic pressure in the newly discovered pyrochlore superconductor RbOs_2O_6 (T_c\simeq6.3K at p=0). A pronounced and {\it positive} pressure effect (PE) on T_c with dT_c/dp…
We have measured the Ca isotope effect in the newly discovered superconductor CaC6. The isotope effect coefficient is 0.50(7). If one assumes that this material is a conventional electron-phonon coupled superconductor, this result shows…
The hydrostatic pressure effect on the newly discovered superconductor MgB2 has been determined. The transition temperature Tc was found to decrease linearly at a large rate of -1.6 K/GPa, in good quantitative agreement with the ensuing…
The optical properties of the superconducting single crystal Rb$_{0.8}$Fe$_{1.68}$Se$_2$ with $T_{c}$ $\simeq$ 31 K have been measured over a wide frequency range in the $ab$ plane. We found that the optical conductivity is dominated by a…
Superconductivity in the recently proposed ground-state structures of atomic metallic hydrogen is investigated over the pressure range 500 GPa to 3.5 TPa. Near molecular dissociation, the electron--phonon coupling $\lambda$ and renormalized…
Electronic structure and electron correlations of the Hubbard model on the Beta-Mn lattice have been investigated on the basis of the momentum dependent local ansatz wavefunction method. It is found that the electrons on the Beta-Mn lattice…
We discuss the electronic structure, lattice dynamics and electron-phonon interaction of newly discovered superconductor LaO$_{0.5}$F$_{0.5}$BiS$_{2}$ using density functional based calculations. A strong Fermi surface nesting at…
To identify the superconducting gap structure in URu2Si2 we perform field-angle-dependent specific heat measurements for the two principal orientations in addition to field rotations, and theoretical analysis based on microscopic…
Observed optical reflectivity in the infrared spectral region is compared with theoretical predictions in a strongly coupled electron-phonon system. Starting from a Froehlich Hamiltonian, the spectral functions and their temperature…