Magnetism in Quasi-One-Dimensional A$_2$Cr$_3$As$_3$ (A=K,Rb) superconductors

TL;DR

This paper predicts strong magnetic fluctuations and a nearby in-out co-planar magnetic ground state in A$_2$Cr$_3$As$_3$ superconductors, linking their magnetic properties to unconventional superconductivity and quantum criticality.

Contribution

It introduces a theoretical prediction of magnetic fluctuations and a specific magnetic ground state in A$_2$Cr$_3$As$_3$ superconductors, explaining their non-Fermi liquid behavior and phase diagram similarities with other unconventional superconductors.

Findings

Strong frustrated magnetic fluctuations in A$_2$Cr$_3$As$_3$

Sensitivity of magnetism to pressure and lattice constant

Potential quantum critical region related to magnetism and superconductivity

Abstract

We predict that the recently discovered quasi-one dimensional superconductors, A$_2$Cr$_3$As$_3$(A=K,Rb), possess strong frustrated magnetic fluctuations and are nearby a novel in-out co-planar magnetic ground state. The frustrated magnetism is very sensitive to c-axis lattice constant and can thus be suppressed by increasing pressure. Our results qualitatively explain strong non-Fermi liquid behaviors observed in the normal state of the superconductors as the intertwining between the magnetism and superconductivity can create a large quantum critical region in quasi-one dimensional systems and also suggest that the materials share similar phase diagrams and superconducting mechanism with other unconventional superconductors, such as cuprates and iron-based superconductors.