Theoretical study of NMR relaxation due to rattling phonons

Abstract

We calculate the NMR relaxation rate due to quadrupolar coupling of the nucleus to a local, strongly anharmonic phonon mode. As a model potential for a rattling motion we consider a square-well potential. We calculate the free phonon Green's function analytically and derive the low and high temperature limits of the NMR relaxation rate. It is shown that the temperature dependence of the NMR relaxation rate possesses a peak in contrast to harmonic phonons but in qualitative agreement with a recent NMR study on KOs2O6. We discuss the influence of phonon renormalization due to electron-phonon interaction.

arXiv comment5 pages, 3 figures, SNS2007 (Sendai, Japan) conference proceedings, accepted for publication

References in corpus (7)

• Extremely strong-coupling superconductivity and anomalous lattice properties in the beta-pyrochlore oxide KOs2O6
• Crystal structure of the pyrochlore oxide superconductor KOs${}_2$O${}_6$
• NMR relaxation and resistivity from rattling phonons in pyrochlore superconductors
• Correlation Effects and Structural Dynamics in the $\beta$-Pyrochlore Superconductor KOs${}_2$O${}_6$
• Second Anomaly in the Specific Heat of beta-Pyrochlore Oxide Superconductor KOs2O6
• NMR Observation of Rattling Phonons in the Pyrochlore Superconductor KOs2O6
• Thermal Conductivity of the Pyrochlore Superconductor KOs2O6: Strong Electron Correlations and Fully Gapped Superconductivity

Cited by in corpus (5)

• Rattling-Induced Superconductiviy in the Beta-Pyrochlore Oxides AOs2O6
• Quantum dynamics of relativistic bosons through nonminimal vector square potentials
• Extrinsic Proton NMR Studies of Mg(OH)${}_2$ and Ca(OH)${}_2$
• Intrinsic Proton NMR Studies of Mg(OH)${}_2$ and Ca(OH)${}_2$
• Anharmonicity in one-dimensional electron-phonon system