Time-reversal symmetry breaking in the superconducting state of ScS

We have studied the electronic properties of ScS, a transition-metal monochalcogenide with a rocksalt crystal structure, using magnetization, specific heat, transport, and muon spin rotation/relaxation (mu SR) measurements. All measurements confirm the bulk superconductivity in ScS with a transition temperature of T-C = 5.1(5) K. Specific heat together with transverse-field mu SR measurements indicate a full gap, while our zero-field mu SR study reveals the presence of spontaneous static or quasistatic magnetic fields emerging when entering the superconducting state. We discuss various possible microscopic origins of the observed time-reversal symmetry breaking. As none of them can be readily reconciled with a conventional pairing mechanism, this introduces ScS as a candidate material for unconventional superconductivity.

Automated summary

We have studied the electronic properties of ScS, a transition-metal monochalcogenide, and confirmed its bulk superconductivity. The presence of spontaneous static or quasistatic magnetic fields in the superconducting state suggests that ScS may be a candidate material for unconventional superconductivity.