Specific Heatof the Filled Skutterudite Superconductor LaOs₄As₁₂

Abstract

We investigated low-temperature specific heat of the filled skutterudite compound LaOs4As12 with a transition temperature Tc = 3.2 K. A moderate size of a specific-heat jump points at a weak electron-phonon coupling in this material. At T < Tc, the electronic contribution to the specific heat was found to be at variance with the predictions for an s-wave superconductor with one energy gap. Additionally, we observed an upward curvature of the upper critical field near the transition temperature. Both features provide some indications towards multiband superconductivity, although anisotropy effects as a viable cause of the observed anomalies in LaOs4As12 cannot be excluded. Similarities to a probable two-band superconductor LaRu4As12 are discussed.

The effective increase in atomic scale disorder by doping and superconductivity in Ca3Rh4Sn13

“…Another possibility can be, e.g., a two-band nature of superconductivity in these systems. Previously, intriguing evidence for multiband effects was also documented in structurally similar filled skutterudite LaRu 4 As 12 [69] and LaOs 4 As 12 [70] compounds.…”

Possible multiband superconductivity in the quaternary carbide YRe2SiC

“…5 K. These anomalies are suppressed by H = 5 T, a field that exceeds Hc2 for T > 1.3 K. The magnitude of the jump corresponding to the larger anomaly in Cp is DCe/gT ≈ 0.8 (figure 4(b)), about 55% of the expected value of 1.43 for the BCS theory. It is plausible that this lower value may be associated with a non-superconducting fraction of material, as frequently observed in other materials, e.g HfV2Ga4, LaOs4As12, and Nb2PdS5[34][35][36].…”

Theoretical investigation of superconductivity mechanism in the filled skutterudites YRu4P12, YOs4P12, LaOs1P12 and LaOs4As12

“…Iwahashi and co-workers [25] reported the Haas-van Alphen effect in LaOs 4 P 12 and found multiply-connected and nearly spherical Fermi surfaces with cyclotron effective mass of 1.1-4.7 m o . Recently, the specific heat measurement of LaOs 4 As 12 has been made by Juraszek and co-workers [28]. This experimental work [28] reveals that a moderate size of specific heat jump signals a weak electron-phonon coupling in this La-based skutterudite compound.…”

“…Recently, the specific heat measurement of LaOs 4 As 12 has been made by Juraszek and co-workers [28]. This experimental work [28] reveals that a moderate size of specific heat jump signals a weak electron-phonon coupling in this La-based skutterudite compound.…”

“…Filled skutterudite pnictides with the general formula LnT 4 X 12 (Ln = Lanthanide, T = Transition metal, X = Pnictogen) have received great attention since they exhibit a variety of individual properties, such as semiconducting [1][2][3][4], metal-insulator transition [5][6][7][8], different magnetic ordering [9][10][11][12][13][14], good thermoelectricity [15][16][17][18], heavy fermion behavior [19,20] and topological insulator behavior [21,22]. Furthermore, the La-based skutterudite compounds have received special interest due to their superconducting properties [23][24][25][26][27][28][29]. In particular, LaOs 4 P 12 and LaOs 4 As 12 exhibit superconductivity below 2.0 and 3.2 K, respectively [23,25].…”