dimer
; article
; chemical structure
; geometry
; kinematics
; low temperature
; magnet
; magnetic field
; magnetism
; molecular dynamics
; nuclear magnetic resonance
; physics
; priority journal
; frustrated magnetism
; kinetically constrained models
; nonequilibrium dynamics and quenches
; reaction-diffusion processes
; Computer Simulation
; Dimerization
; Entropy
; Kinetics
; Magnetics
; Metals, Rare Earth
; Models, Chemical
; Stochastic Processes
英文摘要:
We present nonequilibrium physics in spin ice as a unique setting that combines kinematic constraints, emergent topological defects, and magnetic long-range Coulomb interactions. In spin ice, magnetic frustration leads to highly degenerate yet locally constrained ground states. Together, they form a highly unusual magnetic state-a "Coulomb phase"-whose excitations are point-like defects-magnetic monopoles-in the absence of which effectively no dynamics is possible. Hence, when they are sparse at low temperature, dynamics becomes very sluggish. When quenching the system from a monopole-rich to a monopole-poor state, a wealth of dynamical phenomena occur, the exposition of which is the subject of this article. Most notably, we find reaction diffusion behavior, slow dynamics owing to kinematic constraints, as well as a regime corresponding to the deposition of interacting dimers on a honeycomb lattice. We also identify potential avenues for detecting the magnetic monopoles in a regime of slow-moving monopoles. The interest in this model system is further enhanced by its large degree of tunability and the ease of probing it in experiment: With varying magnetic fields at different temperatures, geometric properties-including even the effective dimensionality of the system-can be varied. By monitoring magnetization, spin correlations or zero-field NMR, the dynamical properties of the system can be extracted in considerable detail. This establishes spin ice as a laboratory of choice for the study of tunable, slow dynamics.
Mostame, S., Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States; Castelnovo, C., Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom; Moessner, R., Max Planck Institute for the Physics of Complex Systems, D-01187 Dresden, Germany; Sondhi, S.L., Department of Physics, Princeton University, Princeton, NJ 08544, United States
Recommended Citation:
Mostame S.,Castelnovo C.,Moessner R.,et al. Tunable nonequilibrium dynamics of field quenches in spin ice[J]. Proceedings of the National Academy of Sciences of the United States of America,2014-01-01,111(2)