Magnetic Lifshitz transition and its consequences in multi-band iron-based superconductors

Abstract

In this paper we address Lifshitz transition induced by applied external magnetic field in a case of iron-based superconductors, in which a difference between the Fermi level and the edges of the bands is relatively small. We introduce and investigate a two-band model with intra-band pairing in the relevant parameters regime to address a generic behaviour of a system with hole-like and electron-like bands in external magnetic field. Our results show that two Lifshitz transitions can develop in analysed systems and the first one occurs in the superconducting phase and takes place at approximately constant magnetic field. The chosen sets of the model parameters can describe characteristic band structure of iron-based superconductors and thus the obtained results can explain the experimental observations in FeSe and Co-doped BaFe2As2 compounds.

Lifshitz Transitions Induced by Magnetic Field

“…[58], and observed in the thermal conductivity measurements in a presence of high magnetic field and at low temperature. The phase transition mentioned above, exists in approximately constant magnetic field independently of temperature, what is in agreement with theoretical calculation [23].…”

“…In this paper we briefly describe the LT induced by external magnetic field, thus it is called as the magnetic Lifshitz transition (MLT) [23,24]. First, we shortly describe the main idea of the MLT (Sect.…”

s+is superconductivity with incipient bands: Doping dependence and STM signatures

“…pressure, doping, external magnetic field 30 or nanostructuring 31 ). Theoretical proposals have been put forward that strong T c enhancement can be achieved close to Lifshitz transition in striped 32,33 and layered systems 34 .…”

Phase Transitions in Quasi-One-Dimensional System with Unconventional Superconductivity

“…Moreover, for magnetic fields larger than the top of the band (i.e. 2t for one-dimensional case studied here), one can find the magnetic Lifshitz transition [40,42]. As a consequence of the relatively strong pairing interaction, the superconductivity still exists in the system, even if the Fermi surface for one type spin disappears.…”