Strain is powerful for discovery and manipulation of new phases of matter; however, elastic strains accessible to epitaxial films and bulk crystals are typically limited to small, uniform, and discrete values. In this talk I will describe our progress on synthesizing single crystalline membranes of Heusler compounds, which enable large continuously tunable strains and strain gradients via bending and rippling [1]. This synthesis strategy borrows ideas from remote epitaxy and van der Waals epitaxy on graphene, and I will describe our current understanding of the growth mechanisms [2,3]. I will then show how strain gradients transform rippled GdPtSb membranes from an antiferromagnet to a room temperature ferromagnet via flexomagnetic coupling [4], and how larger strain gradients induce flexomagnetism [5] and superconductivity in GdAuGe membranes. Finally, I will discuss new efforts on tuning ultrafast magnetism in membranes via combined strain and optical excitation. Our strained Heusler membranes offer a highly tunable platform for discovery of new topological, magnetic, and superconducting phases both in and out of equilibrium.
[1] D. Du, e. al. APL, 122, 170501 (2023).
[2] S. Manzo, et. al., Nature Commun., 13, 4014 (2022).
[3] D. Du et. al., Nano Lett. 22, 21, 8647 (2022).
[4] D. Du, et. al., Nature Commun., 12, 2494 (2021).
[5] Z. LaDuca, et. al. Nano Letters, 23, 33 (2024).