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The dependence of Tc for MgB2 on purely hydrostatic or nearly hydrostatic pressure has been determined to 23 GPa for single-crystalline and to 32 GPa for polycrystalline samples, and found to be in good agreement. Tc decreases from 39 K at…
Raman spectra of the MgB2 ceramic samples were measured as a function of pressure up to 32 GPa at room temperature. The spectrum at normal conditions contains a very broad peak at ~590 cm-1 related to the E2g phonon mode. The frequency of…
The dependence of Tc on nearly hydrostatic pressure has been measured for an isotopically pure (11B) MgB2 sample in a helium-loaded diamond-anvil-cell to nearly 20 GPa. Tc decreases monotonically with pressure from 39.1 K at ambient…
We study the effects of pressure on the electron-phonon interaction in MgB_2 using density-functional-based methods. Our results show that the superconductivity in MgB_2 vanishes by 100 GPa, and then reappears at higher pressures. In…
We present the structural, electronic and superconducting properties of Li2B2 under pressure within the framework of the density functional theory. The structural parameters, electronic band structure, phonon frequency of the E2g phonon…
We have observed a strongly broadened Raman band of MgB2 that shows anomalously large pressure dependence of its frequency. This band and its pressure dependence can be interpreted as the E2g zone center phonon, which is strongly anharmonic…
Measurements of the superconducting transition temperature Tc have been performed by the inductive method on MgB2 at pressures up to 28 GPa. Tc decreases with applied pressure, exhibiting a cusp at about 9 GPa. We interpret the appearance…
The dependence of Tc on hydrostatic (He-gas) pressure has been determined to 0.7 GPa. We find that Tc decreases linearly and reversibly under pressure at the rate dTc/dP = -1.11 +- 0.02 K/GPa. These studies were carried out on the same…
Temperature dependent Raman scattering studies in polycrystalline MgB2(10<T<300 K)reveal that the E2g phonon does not experience any self energy renormalization effect across the superconducting critical temperature Tc ~ 40 K. In contrast,…
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 variation of the superconducting critical temperature Tc as a function of the pressure p in the magnesium diboride MgB2 has been studied in the framework of two-bands Eliashberg theory and traditional phonon coupling mechanism. I have…
The specific heat C of a sintered polycrystalline sample of MgB2 with a bulk superconducting transition temperature Tc=36.7 K is measured as a function of the temperature (2-300 K) and magnetic field (0-16 T), together with magnetic…
The discovery of the first high critical temperature (Tc) transition metal diboride superconductor, MgB2 structure alpha-MoB2 under pressure with Tc up to 32 K at 100 GPa, provides new input into some unexplained aspects of electron-phonon…
The pressure effect on the superconducting transition temperature of MgB2 has been determined using gas pressure up to 1 GPa. The transition temperature Tc was found to decrease linearly at a constant rate over the whole pressure range. The…
High-pressure resistivity experiments were performed on the recently discovered superconductor, MgB2. Tc decreases quasi-linearly with applied pressure to 1.4 GPa at a rate of -2.0(1) K/GPa, which is somewhat larger than that derived from…
The recent discovery of superconductivity at ~39 K in MgB2, by Nagamatsu et al. establishes this simple binary compound as having the highest bulk superconducting transition temperature, Tc, of any non-copper-oxide material. Much of the…
In this paper we report parallel in situ neutron powder diffraction and Tc(P) measurements versus pressure on the same MgB2 sample in a He-gas apparatus to 0.6 GPa; in addition, we present Tc(P) measurements in a helium-loaded…
The effect of high pressures to 40 GPa on the crystal structure and lattice dynamics of AlB2 was studied by synchrotron x-ray powder diffraction, Raman spectroscopy, and first-principles calculations. There are no indications for a…
Measurements of the superconducting transition temperatures for Al-doped, C-doped and neutron-damaged-annealed MgB2 samples under pressure up to ~8 kbar are presented. The dT_c/dP values change systematically with the decrease of the…
Pressure induced electronic topological transitions in the wide band gap semiconductor Sb2S3 (Eg = 1.7-1.8 eV) with similar crystal symmetry (SG: Pnma) to its illustrious analog, Sb2Se3, has been studied using Raman spectroscopy,…