Quantum order by disorder in a semiclassical spin ice
Journal
Physical Review B
Journal Volume
82
Journal Issue
13
Date Issued
2010
Author(s)
Chou, Y. Z.
Abstract
We study the effects of quantum fluctuations in spin ice by considering an S>1 quantum Heisenberg model with a nearest-neighbor ferromagnetic interaction J and a large noncollinear 〈 111 〉 easy-axis anisotropy D on a pyrochlore lattice. For a finite D≫ |J|, the low-energy physics is described by a 〈 111 〉 Ising model with additional second- and third-neighbor exchange couplings of order (J2/D), generated by the quantum fluctuations arising from the transverse components of the exchange coupling. The extensive degeneracy of ground states in the D→∞ limit is lifted, and a q=0 ordered state is selected via the quantum order by disorder mechanism, through a first-order phase transition at low temperatures. © 2010 The American Physical Society.
SDGs
Type
journal article