Magnetism and Superconductivity in (RE)Ni2B2C: The Case of TmNi2B2C

TL;DR

This paper theoretically investigates the coexistence of oscillatory magnetic order and superconductivity in TmNi2B2C, revealing their interaction mechanisms and predicting unique quasiparticle spectrum features.

Contribution

It introduces a theoretical analysis of magnetic and superconducting coexistence in TmNi2B2C, exploring interaction mechanisms and proposing experimental tests.

Findings

Magnetic order and superconductivity interact mainly via exchange interaction.

Quasiparticle spectrum exhibits a line of zeros at the Fermi surface.

Two scenarios for magnetic order origin are proposed and experimentally testable.

Abstract

The recently reported coexistence of an oscillatory magnetic order with the wave vector Q=0.241 \AA^{-1} and superconductivity in TmNi2B2C is analyzed theoretically. It is shown that the oscillatory magnetic order and superconductivity interact predominantly via the exchange interaction between localized moments (LM's) and conduction electrons, while the electromagnetic interaction between them is negligible. In the coexistence phase of the clean TmNi2B2C the quasiparticle spectrum should have a line of zeros at the Fermi surface, giving rise to the power law behavior of thermodynamic and transport properties. Two scenarios of the origin of the oscillatory magnetic order in TmNi2B2C are analyzed: a) due to superconductivity and b) independently on superconductivity. Experiments in magnetic field are proposed in order to choose between them.