  Actively shought since the turn of the century, two-dimensional quantum spin
liquids (QSLs) are exotic phases of matter where magnetic moments remain
disordered even at extremely low temperatures. Despite ongoing searches, QSLs
remain elusive, due to a lack of concrete knowledge of the microscopic
mechanisms that inhibit magnetic order in real materials. Here, we study a
theoretical model for a broad class of frustrated magnetic rare-earth
pyrochlore materials called "quantum spin ices". When subject to an external
magnetic field along the [111] crystallographic direction, the resulting spin
interactions contain a mix of geometric frustration and quantum fluctuations in
decoupled two-dimensional kagome planes. Using large-scale quantum Monte Carlo
simulations, we identify a simple set of interactions sufficient to promote a
groundstate with no magnetic long-range order, and a gap to excitations,
consistent with a $Z_2$ spin liquid phase. This suggests a systematic
experimental procedure to search for two-dimensional QSLs within the broader
class of three-dimensional pyrochlore quantum spin ice materials.
