2023/10/05 by Christiansson, Viktor, Werner, Philipp
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2310.03723
Using ab-initio density functional theory for superconductors (SCDFT), we systematically study the quaternary borocarbides RM2B2C. Treating the retarded (frequency-dependent) interaction W(ω) within the random-phase approximation (RPA), we find good agreement with experiments for the calculated superconducting critical temperature Tc in the nonmagnetic Ni- and Pd-based compounds. We argue that the problem of accurately placing the f-bands within DFT, and possibly the lack of an explicit magnetic pair-breaking mechanism, explain the difficulties of SCDFT in reproducing Tc in members of the magnetic RNi2B2C series (R rare-earth with partially filled 4f). While the calculated Tc is overestimated, SCDFT qualitatively captures the experimentally observed trend along the rare-earth series, which indicates that the electron-phonon couplings and dynamically screened interactions have a significant effect on Tc.