Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 47: Correlated Electrons: Spin Systems and Itinerant Magnets 2
TT 47.5: Vortrag
Freitag, 30. März 2012, 10:30–10:45, H 0104
Quantum Ice : a Quantum Monte Carlo study — •Olga Sikora1,2, Owen Benton1, Nic Shannon1,2,3, Karlo Penc4, Frank Pollmann5, and Peter Fulde5,6 — 1H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK — 2Okinawa Institute of Science and Technology, Okinawa, Japan 904-0495 — 3Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, UK — 4Research Institute for Solid State Physics and Optics, H-1525 Budapest, Hungary — 5Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 6Asia Pacific Center for Theoretical Physics, Pohang, Korea
Spin ice systems with fascinating "magnetic monopole" excitations are characterized by macroscopic degeneracy previously discovered in water ice. At very low temperatures we might expect this degeneracy to be lifted by quantum tunneling between different ice configurations.
Here we present the results of large-scale Green’s function Monte Carlo simulation of ice-type models which include quantum tunneling. We find compelling evidence of an extended quantum U(1)-liquid ground state with deconfined monopole excitations in both the quantum dimer model [1,2] and the quantum ice model on the diamond lattice [3]. We discuss the fate of "pinch point" singularities seen in neutron scattering experiments on spin ice materials, showing how these are "hollowed out" in the quantum ice model [3,4].
O. Sikora et al., Phys. Rev. Lett. 103, 247001 (2009)
O. Sikora et al., Phys. Rev. B 84, 115129 (2011)
N. Shannon et al., arXiv:1105.4196
O. Benton et al., in preparation.