Structural instability and the Mott-Peierls transition in a half-metallic hollandite : K$_{2}$Cr$_{8}$O$_{16}$

Sooran Kim; Kyoo Kim; B. I. Min

doi:10.1103/PhysRevB.90.045124

paper

Structural instability and the Mott-Peierls transition in a half-metallic hollandite : K $_{2}$ Cr $_{8}$ O $_{16}$

arXiv:1403.2803 · doi:10.1103/PhysRevB.90.045124

Abstract

In order to explore the driving mechanism of the concomitant metal-insulator and structural transitions in quasi-one-dimensional hollandite K $_{2}$ Cr $_{8}$ O $_{16}$ , electronic structures and phonon properties are investigated by employing the {\it ab initio} density functional theory (DFT) calculations. We have found that the imaginary phonon frequency reflecting the structural instability appears only in the DFT+ $U$ ( $U$ : Coulomb correlation) calculation, which indicates that the Coulomb correlation plays an essential role in the structural transition. The lattice displacements of the softened phonon at X explain the observed lattice distortions in K $_{2}$ Cr $_{8}$ O $_{16}$ perfectly well, suggesting the Peierls distortion vector {\bf Q} of X (0, 0, 1/2). The combined study of electronic and phonon properties reveals that half-metallic K $_{2}$ Cr $_{8}$ O $_{16}$ , upon cooling, undergoes the correlation-assisted Peierls transition to become a Mott-Peierls ferromagnetic insulator at low temperature.

Structural instability and the Mott-Peierls transition in a half-metallic hollandite : K $_{2}$ Cr $_{8}$ O $_{16}$

Abstract

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Structural instability and the Mott-Peierls transition in a half-metallic hollandite : K2​Cr8​O16​

Abstract

References in corpus (8)

Cited by in corpus (2)

Structural instability and the Mott-Peierls transition in a half-metallic hollandite : K $_{2}$ Cr $_{8}$ O $_{16}$