Superconducting Phase at 7.7 K in theHgxReO3Compound with a Hexagonal Bronze Structure

Abstract

We have successfully synthesized a new rhenium-based hexagonal bronze material, HgxReO3, which exhibits superconductivity with the transition temperature Tc=7.7 K at ambient pressure and 11.1 K at 4 GPa. This compound is a superconductor with the highest Tc among hexagonal bronzes. Moreover, it presents the novel crystallographic feature that (Hg2)2+ polycations, in contrast to monatomic cations in known hexagonal bronzes, are incorporated into open channels. There is evidence that conducting electrons tightly couple with Hg-related phonons. Our results inspire detailed studies on the role of the rattling phonon in the occurrence of superconductivity in the hexagonal bronzes.

Antiferromagnetism and the emergence of frustration in the sawtooth lattice chalcogenide olivines Mn2SiS4−xSex ( xNhalil1, Baral2, Khamala3 et al. 2019Phys. Rev. B101160View full textAdd to dashboardCite

“…This points out that the magnetic structure and the low temperature magnetism of Mn 2 SiS 4−x Se x compounds are more complex than the PM-AFM-WF transitions that were reported earlier. 20,22,25 The presence of α-MnS found in two of the samples through x ray diffraction analysis does not influence the magnetism as α-MnS has a magnetic transition at T = 140 K but we do not observe any anomalies at this temperature in any of the compositions. The effective paramagnetic moment, µ eff and the Curie-Weiss temperature, θ cw are estimated form the inverse magnetic susceptibility versus temperature data following a curve-fit to Curie-Weiss law.…”

“…The experimentally measured specific heat of Mn 2 SiS 4−x Se x (x = 0-4) are presented in Fig 3 (a) where the specific heat under 0 T and 3 T are plotted together. The parent composition, Mn 2 SiS 4 reproduces the antiferromagnetic phase transition at T N ≈ 84 K 20,25,42,43 which characterizes the paramagnetic-to-antiferromagnetic phase transition. It is reported that in the temperature range 83 K-86 K, Mn 2 SiS 4 displays WF; further, below 83 K it is an antiferromagnet.…”

“…Due to this structural feature, the A-site lattice is geometrically magnetically frustrated when it is occupied by magnetic ions 19 . The end-compounds of Mn 2 SiS 4−x Se x -Mn 2 SiS 4 and Mn 2 SiSe 4order antiferromagnetically below their Neél temperature, T N ≈ 83 K and 66 K, respectively [20][21][22][23] . Mn 2 SiS 4 belongs to the class of anisotropic uniaxial antiferromagnets but with anomalous magnetic features near the spin-flop transition 20 .…”

“…The end-compounds of Mn 2 SiS 4−x Se x -Mn 2 SiS 4 and Mn 2 SiSe 4order antiferromagnetically below their Neél temperature, T N ≈ 83 K and 66 K, respectively [20][21][22][23] . Mn 2 SiS 4 belongs to the class of anisotropic uniaxial antiferromagnets but with anomalous magnetic features near the spin-flop transition 20 . A weak ferromagnetic interaction exists in a narrow temperature window between 83 K and 86 K, while displaying uniaxial anisotropy with the b-direction as the easy axis.…”

Electride and superconductivity behaviors in Mn5Si3-type intermetallics

“…40 The magnetic susceptibility in the normal state ( Supplementary Fig. 5) can be fitted to the formula χ = χ 0 + C w /(T − θ), where χ 0 is a temperatureindependent term, C w is the Curie-Weiss constant, and θ is the Weiss temperature.…”