Interstitial doping induced superconductivity at 15.3 K in Nb5Ge3 compound

Abstract

It is reported superconductivity in Nb5Ge3C0.3, an interstitial carbide compound. The temperature dependence of the electrical resistivity, ac-susceptibility, and heat capacity (HC) indicate that a bulk type-II superconductivity appears at TC = 15.3 K. Magneto-resistance measurements suggest an upper critical field of BC2 ∼ 10.6 T and a coherence length of ξ ∼ 55 Å at zero temperature. Neutron diffraction analyzes locate the carbon atoms at the interstitial 2b site of the Mn5Si3 type-structure. Heat capacity data below TC are well described by BCS theory. The size of the jump at TC is in good agreement with the superconducting volume fraction observed in susceptibility measurements. A Debye temperature and Sommerfeld constant were also extracted from heat capacity data as 343 K and 34 mJ/mol K2, respectively.

Electron-phonon superconductivity in C-doped topological nodal-line semimetal Zr$_5$Pt$_3$: A muon spin rotation and relaxation ($μ$SR) study

“…Likewise, T C of Zr 5 Sb 3 decreases with the addition of oxygen until the supresison of the superconducting phase in Zr 5 Sb 3 O [18]. The highest reported T C in this family, however, belongs to Nb 5 Ge 3 C 0.3 [23], with T C = 15.3 K. Recently, Renosto et al reported a comprehensive study of the effects of carbon doping on the superconducting properties of Zr 5 Pt 3 C x [25]. It was found that T C first increases from 6 K (x = 0) to 7 K (x = 0.3) and further decreases monotonously for x > 0.3 [25].…”

“…When combined with superconductors, topological materials could also harbor Majorana quasiparticles with non-Abelian exchange statistics, thus possibly opening the way for the quantum computation era [16]. In this context, a large number of intermetallic compounds with general formula M 5 X 3 (M is either a transition or rare earth metal and X is a metalloid) represent a novel platform to explore a plethora of unique properties [17][18][19][20][21][22][23][24][25][26]. These compounds can crystallize in three different prototypes: (i) orthorhombic Yb 5 Sb 3 (P nma, No.…”

Ta 5 GeB 2 : New T 2 superconductor phase

“…respectively which with doping with small radii elements such as B, N or C have T C 's enhanced to 7.8 K for Nb 5 Si 3 and 15.3 K [6] for Nb 5 Ge 3 [7]. In this case, the superconducting properties are related to a high temperature phase (with a prototype Mn 5 Si 3 with hexagonal symmetry) that is stabilized by the interstitial doping mentioned previously.…”

Superconductivity in Nb5Ir3−xPtxO

“…Although physical properties of many Ti 5 Ga 4 -type compounds are studied [1][2][3][4], the superconductivity is reported only in several compounds [5][6][7][8][9] [5] with the critical temperature T c = 9.3 K, and by increasing the oxygen concentration, T c progressively increases to 10.5 K. In this case, the oxygen addition leads to the shrinkage of c and the expansion of a, which is regarded as the enhancement of one-dimensionality of Nb2 6 and Nb1 atomic chains. The temperature dependence of specific heat of Nb 5 Ir 3 O cannot be reproduced by a single exponential temperature dependence, but explained by a two-gap model [5].…”