Electronic structure of the heavy-fermion superconductor Ce2Ni3Ge5 and its reference Ce2Ni3Si5 compound by ab initio calculations

TL;DR

This study uses ab initio calculations to analyze the electronic structure and Fermi surface topology of the heavy-fermion superconductor Ce2Ni3Ge5 and its non-superconducting counterpart Ce2Ni3Si5, revealing FS nesting properties linked to superconductivity.

Contribution

First detailed ab initio comparison of Ce2Ni3Ge5 and Ce2Ni3Si5 focusing on Fermi surface topology and nesting related to superconductivity.

Findings

Ce2Ni3Ge5 exhibits FS nesting properties supporting antiferromagnetic spin fluctuations.

Both compounds have similar Fermi surface structures with four bands.

FS topology differences are linked to the presence of superconductivity in Ce2Ni3Ge5.

Abstract

Band structures of the pressure-induced, heavy-fermion superconductor Ce2Ni3Ge5 and its non-superconducting, mixed-valence isostructural (Ibam) counterpart Ce2Ni3Si5 have been calculated employing the full-potential local-orbital code. Both the local density approximation (LDA) and LDA+U approaches were applied. These investigations were focused particularly on the topology of the Fermi surfaces (FSs) of the compounds. The results show that the FSs are quite similar in these systems and exist in four bands, containing three-dimensional holelike and electronlike sheets. However, the specific FS nesting properties has been revealed only in Ce2Ni3Ge5. They support a previously postulated presence of antiferromagnetic spin fluctuations (SF) in the heavy-fermion superconducting state of this germanide under pressure. Such SF can be responsible for the pressure-induced unconventional superconductivity in this system.