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Publication

Frustrated Structural Instability in Superconducting Quasi-One-Dimensional K2Cr3As3...

Publication Type
Journal
Journal Name
Physical Review Letters
Publication Date
Page Number
187002
Volume
121
Issue
18

We present density functional theory and neutron total scattering studies on quasi-one-dimensional superconducting K2Cr3As3 revealing a frustrated structural instability. Our first principles calculations find a significant phonon instability, which, under energy minimization, corresponds to a frustrated orthorhombic distortion. In neutron diffraction studies we find large atomic displacement parameters with anomalous temperature dependencies, which result from highly localized orthorhombic distortions of the CrAs sublattice and coupled K displacements. These results suggest a more complex phase diagram than previously assumed for K2Cr3As3 with subtle interplays of structure, electron-phonon, and magnetic interactions.