Extreme strain states in complex oxide membranes

Freestanding 2D layers provide an unprecedented degree of freedom to control physical properties. The recent advances in the thin film epitaxy of a water-soluble layer enable the synthesis of virtually all types of complex oxides as a macroscale freestanding membrane [1]. Based on this synthetic method, we have developed an on-chip platform of complex oxide membranes for which strain states can be continuously tuned by design. In the example of a colossal magnetoresistance material (La_0.7Ca_0.3MnO₃), we successfully applied biaxial strain up to 5% and induced a dramatic shift in the metal-to-insulator transition in ultrathin manganite membranes. This versatile platform - compatible with magnetotransport, structural characterization, and optical probes - enables a new avenue to study oxide thin films and heterostructures beyond epitaxial strain.

[1] D. Lu, D. J. Baek, S. S. Hong, L. F. Kourkoutis, Y. Hikita, & H. Y. Hwang, Nat. Mater. 15, 1255 (2016).