First Principles Calculations of Superconducting Critical Temperature of ThCr$_2$Si$_2$-Type Structure

Abstract

High critical temperature (T c ) superconductor has a great potential in many industrial applications. However, discovering a compound having high T c is still remaining a big challenge for experimental approach due to time-consuming and high cost. In this paper, we investigated the critical temperature (T c ) of several compounds of ThCr 2 Si 2 -type structure (space group I4/mmm) since some of them had already been investigated and trusted as the potential candidates for superconductivity. First principle calculation was performed to compute the critical temperature (T c ) based on allen-dynes equation modification of McMillian formula. In order to confirm our calculation scheme, we compared our result with compounds which had been experimentally determined obtained from NI MS database. The result showed a very good agreement with experimental data. Based on this scheme, finally, we found ThCu 2 Si 2 and ThAu 2 Si 2 which were most likely to exhibit a superconductivity around 3.88 K and 4.27. Since, these compounds have not been studied experimentally, then we futher investigated their electronic properties showing non-negative phonons which indicate the dynamical stability of the compounds at ambient condition. Band structure and DOS analysis showed metallic nature where the highest contributor come from d-orbital of rare-earth element and p-orbital of Si emerging a mixture of covalent, ionic and metallic bonds exists in both the compounds. Finally, we calculated the electron phonon coupling coefficient showing a quite large different (27%) leading to the increment of T c , however, both of compounds possess three dimensional electron-like and hole-like multi-band fermi surface which is related to the phonon mediated which is still under electron-phonon mediated superconductivity. keywords : superconductivity, ThCr 2 Si 2 -type structure, ThCu 2 Si 2 , ThAu 2 Si 2 , critical temperature

Closed-loop superconducting materials discovery

“…AC-susceptibility measurements were conducted using either a Quantum Design Magnetic Properties Measurement (MPMS) System (H DC = 10 Oe, H AC = 1 − 3 Oe, 900 Hz) or a Quantum Design Physical Properties Measurement System (H DC = 10 Oe, H AC = 3 Oe, 1 kHz), measuring T ≥ 2 K. Since prior density function theory (DFT) calculations 52 suggested that CaAg 2 Ge 2 would superconduct near T = 1.5 K, we used the 3 He option with the MPMS to measure from 0.4 K to 1.7 K for that sample in addition to our standard measurement above 2 K.…”

GGA and GGA + U Study of ThMn2Si2 and ThMn2Ge2 Compounds in a Body-Centered Tetragonal Ferromagnetic Phase

“…Even the closer states allowed for simple electron mobility, which over time affected the materials’ conductivity. Moreover, the compounds adopted the tetragonal ThCr 2 Si 2 -type structure with three-dimensional electron and hole-like multiband Fermi surfaces (FSs), as appeared in the majority of the same types [ 46 , 47 ] and other types [ 41 , 48 , 49 ] of compounds that were related to the phonon-mediated types that were currently under electron-phonon mediated superconductivity, according to a few other research studies that calculated Fermi surfaces (FSs). Due to the crossing and overlapping of bands across the Fermi level of energy, as well as the absence of a gap in both spin states when utilizing two separate (PBE–GGA and GGA + U) approximations, the thorium compound ThMn 2 X 2 band structures generally described the full metallic nature.…”