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キーワード:
Chromium compounds; Degrees of freedom (mechanics); Lattice vibrations; Magnetic semiconductors; Molecular dynamics; Paramagnetism; Phonons; Spin fluctuations; Temperature distribution; Thermal conductivity; Vibrations (mechanical), Ab initio molecular dynamics; Adiabatic approach; Dynamic couplings; Magnetic ordering temperatures; Non-adiabatic effect; Spin lattice coupling; Temperature dependence; Two degrees of freedom, Nitrogen compounds
要旨:
We study the mutual coupling of spin fluctuations and lattice vibrations in paramagnetic CrN by combining atomistic spin dynamics and ab initio molecular dynamics. The two degrees of freedom are dynamically coupled, leading to nonadiabatic effects. Those effects suppress the phonon lifetimes at low temperature compared to an adiabatic approach. The dynamic coupling identified here provides an explanation for the experimentally observed unexpected temperature dependence of the thermal conductivity of magnetic semiconductors above the magnetic ordering temperature. © 2018 American Physical Society.
