The transition metal dichalcogenide $4H_b\text{−}{\mathrm{TaS}}_2$ exhibits characteristics of topological edge modes and two-component superconductivity with time-reversal symmetry breaking (TRSB). The nature of the superconducting order parameter is a crucial issue that requires experimental investigation. Here, we report measurements of the magnetic penetration depth using a tunnel-diode-oscillator based technique, as well as the specific heat. Both the specific heat and the change in magnetic penetration depth $\left[\mathrm{\Delta }\lambda \left(T\right)\right]$ display an exponentially activated temperature dependence, providing evidence for nodeless superconductivity in $4H_b\text{−}{\mathrm{TaS}}_2$. Moreover, the deduced superfluid density can be well described by a two-gap $s$-wave model, and such multigap superconductivity is consistent with there being multiple bands crossing the Fermi energy. These results constrain the possible pairing symmetries of $4H_b\text{−}{\mathrm{TaS}}_2$.

Close

PrevNext

View figure in article

• Penetration depth
• Superconducting gap
• Superconductivity
• Superfluid density
• Transition metal dichalcogenides