Atomically Layered Helium Films at Ultralow Temperatures: Model Systems for Realizing Quantum Materials

Abstract

This year is also the 50th anniversary of the discovery of exfoliated graphite as a particularly uniform substrate (Thomy and Duval in J Chim Phys 66:1966, 1969. https://doi.org/10.1051/jcp/196966s21966, J Chim Phys 67:286, 1970. https://doi.org/10.1051/jcp/1970670286, J Chim Phys 67:1101, 1970. https://doi.org/10.1051/jcp/1970671101). In this article, we focus on the study of helium films on graphite-based substrates at ultralow temperatures. We provide a flavour of the historical development of this subject and a perspective on the current status. We discuss how atomically layered helium films provide model systems for the realization of a broad range of quantum materials of generic significance. Future prospects arising from new techniques and new substrates will also be discussed.