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

TL;DR

This paper reports the successful layer-by-layer growth of ultra-thin (111)-oriented frustrated quantum pyrochlore films, enabling new exploration of quantum spin ice phenomena in a quasi-2D platform.

Contribution

It demonstrates the first high-quality epitaxial growth of (111)-oriented quantum pyrochlore thin films, expanding experimental access to quantum spin ice states.

Findings

Films are highly crystalline and compositionally accurate.

Growth method enables large-area, planar (111)-oriented quantum spin ice structures.

This platform allows strain and magnetic field studies in the quasi-2D limit.

Abstract

Frustrated rare-earth pyrochlore titanates, Yb$_2$Ti$_2$O$_7$, and Tb$_2$Ti$_2$O$_7$ 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 application of a (111)-oriented external magnetic field. Here, we report on the primal successful layer-by-layer growth of ultra-thin films of frustrated quantum pyrochlores, R$_2$Ti$_2$O$_7$ (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 strain and magnetic field dependent properties in the quasi-2D limit.