Two-gap superconductivity in Ag_1–xMo₆S₈Chevrel phase

Abstract

The superconducting properties of [Formula: see text]MoS [[Formula: see text]] Chevrel phase [[Formula: see text] K] are studied on a sample compacted by spark plasma sintering. Both lower ([Formula: see text] mT) and the upper [[Formula: see text] T] critical magnetic fields are obtained from magnetization and electrical resistivity measurements for the first time. The analysis of the low-temperature electronic specific heat indicates [Formula: see text]MoS to be a two band superconductor with the energy gaps [Formula: see text] meV (95%) and [Formula: see text] meV (5%). Theoretical DFT calculations reveal a much stronger electron-phonon coupling in the studied Chevrel phase compared to earlier reports. Similar to MgB, the Fermi surface of studied Chevrel phase is formed by two hole-like and one electron-like bands.

Superconducting properties of pseudobinary telluride Chevrel Phase Mo$_4$Re$_2$Te$_8$

“…Moreover, the resistivity trend in high temperature region for Mo 4 Re 2 Te 4 consists of negative curvature (dρ/dT ) with the nearly saturated resistivity, indicating an additional contribution in the system with the metallic nature. This behaviour is reminiscent of the other Chevrel phase, skutterudites, and clathrates compounds consisting of similar type of cluster structures [3,[36][37][38][39]. Moreover, the same trend is also observed in La 7 X 3 (X = Rh, Ir) family and YCo 2 , where the electronic scattering is related to the excitations with a broad spectrum of energy is stated the possible reason for the resistivity trend [40,41].…”

“…Even though, the high DOS at the Fermi level, large contribution to the lattice specific heat, β 3 and parameter γ n /T C = 7.6 mJmol −1 K −3 of Mo 4 Re 2 Te 8 are comparable to SnMo 6 S 8 , PbMo 6 S 8 and Ag 1−x Mo 6 S 8 , possessing strong electron-phonon coupling, Mo 4 Re 2 Te 8 has moderate coupling. The ratio γ n /T C indicates the scale of transition temperature with the density of states at E F [3,4].…”

“…Chevrel phase (CP) is one of the crucial members of the unconventional superconductor family, providing a broader aspect of interactions and structural impact on the superconducting ground state [1]. This phase has a perplexing array of unconventional superconducting properties such as extremely high upper critical magnetic field, multicomponent and multiband superconductivity, magnetic field driven or magnetically ordered superconductivity, reentrant superconductivity, and many more [2][3][4][5][6][7][8]. Additionally, the coupling manner of building blocks (Mo clusters) of classical CPs multi-folds various crystal structures [9][10][11][12] producing quasi-1D superconductor [13] and exhibiting interesting topological properties [14].…”

Superconducting Chevrel phase PbMo$_{6}$S$_{8}$ from first principles

“…Nevertheless, the origin of the superconducting transition in Chevrel phases is attributed to the electronphonon mechanism 13,20,21 . In addition, a recent experiment reports the appearance of a double SC gap in PbMo 6 S 8 , SnMo 6 S 8 and AgMo 6 S 8 22,23 . Attempts to clarify the situation with modern theoretical methods have been scarce, and few works provide ab initio results on the topic 6,7,21 .…”

Superconducting properties of pseudobinary telluride Chevrel phase Mo4Re2Te8

“…The Chevrel phase (CP) superconductor is a crucial member of the unconventional superconductor family, providing a broader aspect of interactions and structural impact on the superconducting ground state [1]. The CP has a perplexing array of unconventional superconducting properties, including an extremely high upper critical magnetic field, multicomponent and multiband superconductivity, magnetic field-driven or magnetically ordered superconductivity, reentrant superconductivity and many more [2][3][4][5][6][7][8]. Additionally, classical CPs exhibit various crystal structures based on the coupling manner of its building blocks (or Mo clusters) [9][10][11][12], which produces quasi-1D superconductors [13] and interesting topological properties [14].…”