Year: 2011
Type: article
Abstract: We investigated the superconducting gap structure of SrNi${}_{2}$P${}_{2}$ (${T}_{\mathrm{c}}=1.4$ K) via low-temperature magnetothermal conductivity $\ensuremath{\kappa}(T,H)$ measurements. Zero field thermal conductivity $\ensuremath{\kappa}$ decreases exponentially $\ensuremath{\kappa}\ensuremath{\propto}$ exp($\ensuremath{-}{\mathit{aT}}_{\mathrm{c}}/T$) with $a=$ 1.5, in accord with the BCS theory, and rolls over to a phonon-like $\ensuremath{\kappa}\ensuremath{\propto}{T}^{3}$ behavior at low temperature, similar to a number of conventional $s$-wave superconductors. In addition, we observed a ``concave'' field dependence of the residual linear term ${\ensuremath{\kappa}}_{0}(H)/T$. These facts strongly rule out the presence of nodes in the superconducting energy gap of SrNi${}_{2}$P${}_{2}$. Together with a fully gapped Fermi surface in the superconducting state of BaNi${}_{2}$As${}_{2}$ (${T}_{\mathrm{c}}=$ 0.6--0.7 K), demonstrated in our recent work, these results lead us to stipulate that fully gapped superconductivity is likely to be a universal feature of Ni-based pnictide superconductors.
Source: Physical Review B
Language: Latvian
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2129203376