Quantum muon diffusion and the preservation of time-reversal symmetry in the superconducting state of type-I rhenium

Abstract

Elemental rhenium exhibiting type-II superconductivity has been previously reported to break time-reversal symmetry in the superconducting state. We have investigated an arc-melted sample of rhenium exhibiting type-I superconductivity. Low-temperature zero-field muon-spin relaxation measurements indicate that time-reversal symmetry is preserved in the superconducting state. Muon diffusion is observed, which is due to quantum mechanical tunneling between interstitial sites. The normal state behavior is characterized by the conduction electrons screening the muons and thermal broadening, and is typical for a metal. Energy asymmetries between muon trapping sites and the superconducting energy gap also characterize the superconducting state behavior.

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

“…Such as Re 6 X (X = Zr, Hf, Ti), a noncentrosymmetric family shows spontaneous field presence, breaking TRS, regardless of the element X [25][26][27], while the other non-centrosymmetric compounds Re 3 Y (Y = Ta, W) and the Re-B system [28][29][30], preserve time-reversal symmetry. Furthermore, the uncertainty in TRS breaking presence in centrosymmetric Re is also intriguing [31,32] and raises more questions about the role of associated structure and Re concentration in time reversal symmetry breaking. In this regard, investigating more Re based superconductors are essential and Re based pseudobinary telluride CP Mo 4 Re 2 Te 8 , provides that platform with a new structural aspect and different Re concentration.…”