Finite temperature spin-dynamics and phase transitions in spin-orbital models
We study finite temperature properties of a generic spin-orbital model relevant to transition metal compounds, having coupled quantum Heisenberg-spin and Ising-orbital degrees of freedom. The model system undergoes a phase transition, consistent with that of a 2D Ising model, to an orbitally ordered state at a temperature set by short-range magnetic order. At low temperatures the orbital degrees of freedom freeze-out and the model maps onto a quantum Heisenberg model. The onset of orbital excitations causes a rapid scrambling of the spin spectral weight away from coherent spin-waves, which leads to a sharp increase in uniform magnetic susceptibility just below the phase transition, reminiscent of the observed behavior in the Fe-pnictide materials.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 979042
- Report Number(s):
- SLAC-PUB-14003
- Journal Information:
- Submitted to Physical Review B, Journal Name: Submitted to Physical Review B
- Country of Publication:
- United States
- Language:
- English
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