arXiv subjects

Elbert E. M. Chia

Publications and source records attributed to Elbert E. M. Chia.

39 records · Page 3Linked to original sources

arXiv2004

Probing the superconducting gap symmetry of PrRu$_{4}$Sb$_{12}$: A comparison with PrOs$_{4}$Sb$_{12}$

We report measurements of the magnetic penetration depth $λ$ in single crystals of PrRu$_{4}$Sb$_{12}$ down to 0.1 K. Both $λ$ and superfluid density $ρ_{s}$ exhibit an exponential behavior for $T$ $<$ 0.5$T_{c}$, with parameters $Δ$(0)/\textit{k}$_{B}$\textit{T}$_{c}$ = 1.9 and $λ(0)$ = 2900 Å. The value of $Δ$(0) is consistent with the specific-heat jump value of $ΔC/γT_{c}$ = 1.87 measured elsewhere, while the value of $λ(0)$ is consistent with the measured value of the electronic heat-capacity coefficient $γ$. Our data are consistent with PrRu$_{4}$Sb$_{12}$ being a moderate-coupling, fully-gapped superconductor. We suggest experiments to study how the nature of the superconducting state evolves with increasing Ru substitution for Os.

cond-mat.supr-con↗

arXiv2003

Probing the superconducting gap symmetry of PrOs$_{4}$Sb$_{12}$: A penetration depth study

We report measurements of the magnetic penetration depth $λ$ in single crystals of PrOs$_{4}$Sb$_{12}$ down to $\sim$0.1 K using a tunnel-diode based, self-inductive technique at 21 MHz, with the ac field applied along the \textit{a}, \textit{b} and \textit{c} directions. In all three field orientations the penetration depth and superfluid density $ρ_{s}$ tend to follow a power law, $λ\sim \mathit{T}^{2}, ρ_{s} \sim \mathit{T}% ^{2}$ at low temperatures. $ρ_{s}$ for various gap functions have been calculated, and data is best fit by the $^{3}$He A-phase-like gap with multidomains, each having two point nodes along a cube axis, and parameter $Δ_{0}$(0)/\textit{k}$_{B}$\textit{T}$_{c}$ = 2.6. This suggests that PrOs$_{4}$Sb$_{12}$ is a strong-coupling superconductor with two point nodes on the Fermi surface. We also confirm the observation of the double transitions at 1.75 K and 1.85 K seen in other measurements.

cond-mat.supr-con↗

arXiv2002

Non-Locality and Strong Coupling in the Heavy Fermion Superconductor CeCoIn$_{5}$: A Penetration Depth Study

We report measurements of the magnetic penetration depth $λ$ in single crystals of CeCoIn$_{5}$ down to $\sim$0.14 K using a tunnel-diode based, self-inductive technique at 28 MHz. While the in-plane penetration depth tends to follow a power law, $λ_{//} \sim {\it T}^{3/2}$, the data are better described as a crossover between linear ({\it T} $\gg $ ${\it T}^\ast $) and quadratic ({\it T} $\ll {\it T}^\ast $) behavior, with ${\it T}^\ast $ the crossover temperature in the strong-coupling limit. The {\it c}-axis penetration depth $λ_{\perp} $ is linear in {\it T}, providing evidence that CeCoIn$_{5}$ is a {\it d}-wave superconductor with line nodes along the {\it c}-axis. The different temperature dependences of $λ_{//} $ and $λ_{\perp} $ rule out impurity effects as the source of ${\it T}^{\ast} $.

cond-mat.supr-con↗