Epitaxial stabilization of (111)-oriented frustrated quantum pyrochlore thin films

Abstract

Frustrated rare-earth pyrochlore titanates, Yb2Ti2O7 and Tb2Ti2O7, have been proposed as promising candidates to realize quantum spin ice (QSI). Multiple exotic quantum phases, including Coulombic ferromagnet, quantum valence bond solid, and quadrupolar ordering, have been predicted to emerge in the QSI state upon the application of a (111)-oriented external magnetic field. Here, we report on the successful layer-by-layer growth of thin films of the frustrated quantum pyrochlores, R2Ti2O7 (R=Er, Yb, and Tb), along the (111) direction. We confirm their high crystallinity and proper chemical composition by a combination of methods, including in situ RHEED, x-ray diffraction, reciprocal space mapping, and x-ray photoelectron spectroscopy. The availability of large area (111)-oriented QSI structures with planar geometry offers a new complementary to the bulk platform to explore the strain and the magnetic field-dependent properties in the quasi-2D limit.