Van Hove scenario and superconductivity in full Heusler alloy Pd2ZrGa

Abstract

Ab-initio band structure calculation using the state-of-the-art density functional theory was carried out for the sample Pd2ZrGa. The equilibrium lattice parameter was found by fitting the energy vs volume data to Murnaghan equation of state and the value was observed to be 6.467 Å. Non analytical behavior of the energy functional was observed in band structure as well as in density of states diagram near the Fermi level. Polycrystalline sample synthesized using arc-furnace showed compositional variation in X-ray diffraction and energy dispersive analysis of X-ray spectrum studies. Magnetic measurements showed Meissner diamagnetic shielding in the as-cast sample below 2 K. From the Zero Field Cooled (ZFC) and Field Cooled (FC) measurements, we observed that the system is a type II BCS superconductor. The volume susceptibility at 2 K was observed to be 3.1 emu/Oe cm3.

Predicted superconductivity of Ni2VAl and pressure dependence of superconductivity in Ni2NbX (X = Al, Ga and Sn) and Ni2VAl

“…The van Hove singularity is observed in both valence and conduction bands at the L-point close to E F around 1 eV and −1 eV energy range. From earlier available reports [31][32][33], one saddle point is observed in Pd based compounds, at as expected. In table 2, we have given the single crystalline elastic constants along with calculated Debye temperature values.…”

“…Another interesting feature that connects with superconductivity is the presence of van Hove singularities [30], in the electronic structure, leading to peaks in the density of states as found in some of the Pd based Huesler compounds [31][32][33]. Interesting behaviour might be anticipated if the Fermi level can be brought to this peak by means of alloying.…”

Are AuPdTM (T = Sc, Y and M = Al, Ga, In), Heusler Compounds Superconductors without Inversion Symmetry?

“…Moreover, θD may be substituted by the Fermi temperature θF, which allows higher transition temperatures compared with BCS theory. This so-called van Hove scenario has been considered as an example for explaining the unusually high transition temperatures of the intermetallic A15 superconductors [17], cuprate superconductors [18], and Heusler compounds [15,19].…”

First‐Principles Study of the Structural, Phase‐Stability, Electronic, Magnetic, and Elastic Properties of Heusler Alloys VXRh2 (X=Si, Ge, and Sn)

“…[ 2 ] Heusler alloys, which are essentially divided into three groups, binary, [ 3 ] ternary, and quaternary alloys, [ 4 ] contain a broad range of combinations. Most studies are currently focused on superconductivity, [ 5 ] semiconductivity, thermoelectric [ 6 ] properties, magnetic memory, [ 7 ] magnetoresistance, [ 8 ] magnetocaloric, [ 4 ] and low‐temperature stability [ 9 ] of these alloys. Also, these have a significant effect on length changes due to the magnetic field, which is used in the construction of sensors.…”

“…For example, nonmagnetic (NM) Heusler alloys with 27 valence electrons per formula unit are superconducting. [ 5 ] In addition, semiconductor‐like features are seen in full Heusler alloys with 24 valence electrons per formula unit [ 17 ] and half‐Heusler alloys with 18 valence electrons per formula unit. [ 18 ] Many full Heusler alloys with an L2 1 structure are predicted to be half‐metallic ferromagnets using first‐principles simulations.…”