Nodeless superconductivity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>β</mml:mi><mml:mtext>−</mml:mtext><mml:msub><mml:mi>PdBi</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Jian Chen, An Wang, G. M. Pang, Hang Su, Ye Chen, Huiqiu Yuan
Abstract
The superconducting gap symmetry of $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{PdBi}}_{2}$ is studied by measuring the London penetration depth $\mathrm{\ensuremath{\Delta}}\ensuremath{\lambda}(T)$ as well as the heat capacity ${C}_{P}(T,B)$. In the low temperature limit, both the penetration depth $\mathrm{\ensuremath{\Delta}}\ensuremath{\lambda}(T)$ and the electronic specific heat ${C}_{e}(T)/T$ follow exponential-type temperature dependence, providing evidence for fully gapped superconductivity in this compound. Analysis of the superfluid density ${\ensuremath{\rho}}_{s}(T)$ suggests single-gap $s$-wave superconductivity for $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{PdBi}}_{2}$, which is further supported by the linear field dependence of the Sommerfeld coefficient ${\ensuremath{\gamma}}_{0}(B)$ determined in the superconducting state.