Conventional type-II superconductivity in locally non-centrosymmetric LaRh${}_2$As${}_2$ single crystals

Abstract

We report on the observation of superconductivity in LaRh${}_2$As${}_2$, which is the analogue without $f$-electrons of the heavy-fermion system with two superconducting phases CeRh${}_2$As${}_2$. A zero-resistivity transition, a specific-heat jump and a drop in magnetic ac susceptibility consistently point to a superconducting transition at a transition temperature of $T_c=0.28$\,K. The magnetic field-temperature superconducting phase diagrams determined from field-dependent ac-susceptibility measurements reveal small upper critical fields ${\mu }_0{H}_{c2}\approx 12$\,mT for $H\parallel ab$ and ${\mu }_0{H}_{c2}\approx 9$\,mT for $H\parallel c$. The observed $H_{c2}$ is larger than the estimated thermodynamic critical field $H_c$ derived from the heat-capacity data, suggesting that LaRh${}_2$A$s_2$ is a type-II superconductor with Ginzburg-Landau parameters ${\kappa }_{GL}^{ab}\approx 1.9$ and ${\kappa }_{GL}^c\approx 2.7$. The microscopic Eliashberg theory indicates superconductivity to be in the weak-coupling regime with an electron-phonon coupling constant ${\lambda }_{e-ph}\approx 0.4$. Despite a similar $T_c$ and the same crystal structure as the Ce compound, LaRh${}_2$As${}_2$ displays conventional superconductivity, corroborating the substantial role of the 4$f$ electrons for the extraordinary superconducting state in CeRh${}_2$As${}_2$.

11 pages, 8 figures

References in corpus (11)

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• Evidence for time-reversal symmetry breaking in the non-centrosymmetric superconductor LaNiC${}_2$
• Field-induced transition from even to odd parity superconductivity in CeRh${}_2$As${}_2$
• Coexistence of Superconductivity and Charge Density Wave in SrPt2As2
• Superconductivity in novel Ge-based skutterudites: {Sr,Ba}Pt_4Ge_{12}
• Possible quadrupole density wave in the superconducting Kondo lattice CeRh2As2
• Topological crystalline superconductivity in locally noncentrosymmetric CeRh${}_2$As${}_2$
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• Exceptional type-I superconductivity of the layered silver oxide Ag${}_5$Pb${}_2$O${}_6$
• Two-dimensional XY-type Magnetic Properties of Locally Noncentrosymmetric Superconductor CeRh${}_2$As${}_2$
• Intrinsic ac anomalous Hall effect of nonsymmorphic chiral superconductors with an application to $\mathrm{UP}{\mathrm{t}}_3$

Cited by in corpus (8)

• Violation of the Pauli-Clogston limit in a heavy Fermion superconductor CeRh${}_2$As${}_2$ --Duality of itinerant and localized 4f electrons--
• Discovery of magnetic phase transitions in heavy-fermion superconductor CeRh${}_2$As${}_2$
• Coexistence of near-EF flat band and van Hove singularity in a two-phase superconductor
• Spectroscopic evidence of Kondo-induced quasi-quartet in CeRh${}_2$As${}_2$
• Exposing the odd-parity superconductivity in CeRh${}_2$As${}_2$ with hydrostatic pressure
• Conventional $s$-wave Superconductivity in LaRh${}_2$As${}_2$; the Analog without the 4$f$ Electrons of CeRh${}_2$As${}_2$
• La substitution studies on the heavy-fermion superconductor CeRh${}_2$As${}_2$
• Multipolar fluctuations from localized 4f electrons in CeRh2As2