Abstract
Recent experiments on the spin-ice material suggest that the Pauling “ice entropy,” characteristic of its classical Coulombic spin-liquid state, may be lost at low temperatures [Pomaranski et al., Nat. Phys. 9, 353 (2013)]. However, despite nearly two decades of intensive study, the nature of the equilibrium ground state of spin ice remains uncertain. Here we explore how long-range dipolar interactions , short-range exchange interactions, and quantum fluctuations combine to determine the ground state of dipolar spin ice. We identify the organizational principle that ordered ground states are selected from a set of “chain states” in which dipolar interactions are exponentially screened. Using both quantum and classical Monte Carlo simulation, we establish phase diagrams as a function of quantum tunneling and temperature , and find that only a very small is needed to stabilize a quantum spin liquid ground state. We discuss the implications of these results for .
13 More- Received 20 September 2014
- Revised 29 July 2015
DOI:https://doi.org/10.1103/PhysRevB.92.094418
©2015 American Physical Society