Superconductivity in LiGa2Ir Heusler type compound with VEC = 16

Abstract

Polycrystalline LiGa2Ir has been prepared by a solid state reaction method. A Rietveld refinement of powder x-ray diffraction data confirms a previously reported Heusler-type crystal structure (space group Fm-3m, No. 225) with lattice parameter a = 6.0322(1) Å. The normal and superconducting state properties were studied by magnetic susceptibility, heat capacity, and electrical resistivity techniques. A bulk superconductivity with Tc = 2.94 K was confirmed by detailed heat capacity studies. The measurements indicate that LiGa2Ir is a weak-coupling type-II superconductor ($${\uplambda }$$ λ e–p = 0.57, $${\Delta }$$ Δ C/$${\upgamma }$$ γ Tc = 1.4). Electronic structure, lattice dynamics, and the electron–phonon interaction are studied from first principles calculations. Ir and two Ga atoms equally contribute to the Fermi surface with a minor contribution from Li. The phonon spectrum contains separated high frequency Li modes, which are seen clearly as an Einstein-like contribution in the specific heat. The calculated electron–phonon coupling constant $${\uplambda }$$ λ e–p = 0.68 confirms the electron–phonon mechanism for the superconductivity. LiGa2Ir and recently reported isoelectronic LiGa2Rh are the only two known representatives of the Heusler superconductors with the valence electron count VEC = 16.

MgPdSb─An Electron-Deficient Half-Heusler Phase

“…Three distinct bands cross the Fermi level (Figure 4a), resulting in a Fermi surface (FS) depicted in Figure 4c. The overall shape of the FS is similar to the one found in full-Heusler compounds, such as LiGa 2 Ir, 34 LiPd 2 Ge, 35 and MgPd 2 Sb. 19 The electronic DOS around the Fermi level is mostly contributed by Pd d and Sb p states (Figure 4b).…”

First-Principles Calculations to Investigate the Stability and Thermodynamic Properties of a Newly Exposed Lithium–Gallium–Iridium-Based Full-Heusler Compound

“…Several researchers from all over the world have focused on Heusler metals because of their tunable properties, including their high Curie temp, tunable electronics structure, acceptable semiconducting lattice parameter, and varied magnetic property. − Heusler alloy intermetallic compounds are attractive options for thermoelectric materials − and topological insulators. , They can also be used as shape-memory materials, spin-gapless semiconductors, and other forms of thermoelectric materials. − Heusler substances can be broadly categorized into half-Heusler, full-Heusler, and last, quaternary-Heusler. These structures’ stoichiometric configurations are XYZ, XY 2 Z, and XYMZ, in which X, Y, and M are typically transition metals and Z is the leading group component. − XY 2 Z, a full-Heusler configuration, settles in a cubic L2 1 arrangement (MnCu 2 Al-sample) with the spatial group Fm 3̅ m (# 225). ,, In this article, we will investigate the physical characteristics of one such type. LiGa 2 Ir Heusler is a relatively new intermetallic compound that has attracted attention in the scientific community due to its unique combination of physical and superconducting properties .…”

Revealing the electronic, optical, elastic, mechanical, anisotropic, and thermoelectric responses of Sc2NiZ (Z = Si, Ge, and Sn) Heusler alloys via DFT calculations

“…Heusler alloys can be divided into four main groups according to their valence electron numbers as half, full, inverse and quaternary Heusler alloys. Also, half Heusler alloys have the XYZ atom order, where X and Y represent the metals from the d‐block of the periodic table of the elements and Z symbolizes any non‐metallic p‐block member [2, 5–9]. The full Heusler alloys, however, have the X 2 YZ formula where X atom valence electrons are higher than the Y atom.…”

“…Inverse Heusler alloys also display X 2 YZ structure and the Y atom holds more valence electrons than X atoms obeying the Slater‐Pauling rule. In the last group, quaternary Heusler alloys have XX'YZ atoms with the X > X′ > Y valence electron sequence [1–9]. Depending on their compositions, Heusler alloys exhibit desired advantages i.e., superconductivity, heavy fermion behavior, thermoelectricity, high‐magnetic moments, high‐magnetic anisotropy, etc.…”

“…Including both former experimental and theoretical inquiries [2,[5][6][7][8][9], the existing literature does not still report any detailed research regarding Sc 2 NiZ Heusler alloys even though they were first introduced in 2019 [10]. We aim to end this shortage and contribute to the interested audience by analyzing the titled properties of Sc 2 NiZ Heusler alloys.…”