{Multiband Superconductivity in Lu${}_3$Os${}_4$Ge${}_{13}$

Abstract

Intermetallic R${}_3$T${}_4$X${}_{13}$ series consists of cage like structure and have been in focus due to their unconventional electronic ground states. In this work, we report the normal and superconducting state properties of a high quality single crystal of Lu${}_3$Os${}_4$Ge${}_{13}$. Lu${}_3$Os${}_4$Ge${}_{13}$ belongs to the above mentioned series and crystallizes in a cubic crystal structure with the space group $Pm\bar{3}n$. Using electrical transport, magnetization and heat capacity measurements, we show that Lu${}_3$Os${}_4$Ge${}_{13}$ is a type-II multi-band superconductor ($T{}_c=3.1$~K) with unusual superconducting properties. The analysis of the low temperature heat capacity data suggests that Lu${}_3$Os${}_4$Ge${}_{13}$ is a moderately coupled multi-band BCS superconductor with two gaps ($2\Delta /k{}_{B}T{}_c=3.68\pm 0.04\&0.34\pm 0.02$) in the superconducting state. The dc-magnetization ($M-H$) shows a large reversible region in the superconducting state similar to the vortex liquid phase observed in high-$T{}_c$ superconductors. The value of the Ginzburg number $G_i$ suggests that the thermal fluctuations, though small as compared to those in high-$T{}_c$ cuprates, may play an important role in the unpinning of the vortices in this compound. The electronic band structure calculations show that three bands cross the Fermi level and constitute a complex Fermi surface in Lu${}_3$Os${}_4$Ge${}_{13}$

12 pages, 6 figures

References in corpus (2)

• Superfluid density and specific heat within self-consistent scheme for two-band superconductor
• Superconductivity of La${}_3$Co${}_4$Sn${}_{13}$ and La${}_3$Rh${}_4$Sn${}_{13}$: A comparative study

Cited by in corpus (7)

• Superconducting Properties of the Non-Centrosymmetric Superconductor Re6Hf
• Ferromagnetic ordering of minority Ce${}^{3+}$ spins in a quasi-skutterudite Ce${}_3$Os${}_4$Ge${}_{13}$ single crystal
• Probing the superconducting ground state of noncentrosymmetric high entropy alloys using muon-spin rotation and relaxation
• Nodeless superconductivity and the peak effect in the quasi-skutterudites ${\mathrm{Lu}}_3{\mathrm{Os}}_4{\mathrm{Ge}}_{13}$ and ${\mathrm{Y}}_3{\mathrm{Ru}}_4{\mathrm{Ge}}_{13}$
• Time-reversal symmetry breaking in superconducting low-carrier-density quasi-skutterudite Lu3Os4Ge13
• Broken time-reversal symmetry in cubic skutterudite-like superconductor Y${}_3$Ru${}_4$Ge${}_{13}$
• Anomalous temperature dependence of the electrical resistivity in R${}_3$Co${}_4$Ge${}_{13}$ (R = Y, Lu) single crystals