Phonon anomalies and superconductivity in the Heusler compound YPd2Sn

Abstract

We have studied the structural and electronic properties of YPd2Sn in the Heusler structure using a generalized gradient approximation of the density functional theory and the ab initio pseudopotential method. The electronic results indicate that the density of states at the Fermi level is primarily derived from Pd d states, which hybridize with Y d and Sn p states. Using our structural and electronic results, phonons and electron-phonon interactions have been studied by employing a linear response approach based on the density functional theory. Phonon anomalies have been observed for transverse acoustic branches along the [110] direction. This anomalous dispersion is merely a consequence of the strong coupling. By integrating the Eliashberg spectral function, the average electron-phonon coupling parameter is found to be λ = 0.99. Using this value, the superconducting critical temperature is calculated to be 4.12 K, in good accordance with the recent experimental value of 4.7 K.

Pressure effects on the superconductivity of theHfPd2AlHeusler compound: Experimental and theoretical study

“…Thus the observed soft mode behavior may be a more general property of this group of Heusler alloys. Phonon anomalies were also recently observed in superconducting YPd2Sn Heusler compound 48 . Now returning to the analysis of electron-phonon coupling, the average square phonon frequencies, calculated using partial phonon densities for 0 and 7.45 GPa are collected in Table I.…”

Theoretical investigation of antisymmetric spin-orbit coupling effect on the physical properties of noncentrosymmetric BaPtSb superconductor

“…[Huseyin, please check the above statement and let me know if you would prefer to change it.] We have to emphasize that this softening may play a substantial role in developing superconductivity in BaPtSb because a similar observation has been made for other superconductors [42][43][44]. The high frequency region of the phonon spectrum contains two optical phonon bands which exhibit a much reduced level of dispersion than the four optical phonon bands in the low-frequency region.…”

Electron-phonon coupling in the magnetic Weyl semimetal ZrCo2Sn

“…The mechanical stability of ZrCo 2 Sn in the cubic F m3m phase is also verified by the analysis of the calculated elastic constants: C 11 = 290.7 GPa, C 12 = 88.4 GPa, and C 44 = 129.6 GPa. We did not find any phonon anomaly in the phonon spectrum, unlike many other Heusler compounds, where acoustic modes tend to soften, and related anomalies were found in calculations of transverse acoustic branches along the [110] direction [35,36]. Unfortunately, there are no experimental data on the phonon spectrum of ZrCo 2 Sn for comparison.…”

“…These modes, with an energy of about 22 eV at the point, belong to the threefold degenerate symmetry class T 2g and are Raman active. Interestingly, these phonons make a large contribution to e-ph scattering in YPd 2 Sn, a superconducting Heusler compound with the same cubic structure, also only near the zone center [35].…”