Perspective: strain and strain gradient engineering in membranes of quantum materials

Abstract

Strain is powerful for discovery and manipulation of new phases of matter; however, the elastic strains accessible to epitaxial films and bulk crystals are typically limited to small ($<2\%$), uniform, and often discrete values. This Perspective highlights new directions for strain and strain gradient engineering in free-standing single crystalline membranes of quantum materials. Membranes enable large ($\sim 10\%$), continuously tunable strains and strain gradients via bending and rippling. Moreover, strain gradients break inversion symmetry to activate polar distortions, ferroelectricity, chiral spin textures, novel superconductivity, and topological states. Recent advances in membrane synthesis by remote epitaxy and sacrificial etch layers enable extreme strains in new materials, including transition metal oxides and Heusler compounds, compared to natively van der Waals (vdW) materials like graphene. We highlight new opportunities and challenges for strain and strain gradient engineering in membranes of non-vdW materials.

References in corpus (13)

• Metastable ferroelectricity in optically strained $SrTi{O}_3$
• Oxide spintronics
• Half-Heusler Compounds as a New Class of Three-Dimensional Topological Insulators
• Zero-energy vortex bound state in the superconducting topological surface state of Fe(Se,Te)
• Strain-induced partially flat band, helical snake states, and interface superconductivity in topological crystalline insulators
• Topological $R$PdBi half-Heusler semimetals: a new family of non-centrosymmetric magnetic superconductors
• Large magnetoelectric coupling in multiferroic oxide heterostructures assembled via epitaxial lift-off
• Pseudo-magnetic field-induced ultra-slow carrier dynamics in periodically strained graphene
• First-principles theory of spatial dispersion: Dynamical quadrupoles and flexoelectricity
• Controlling the balance between remote, pinhole, and van der Waals epitaxy of Heusler films on graphene/sapphire
• Phase-field modeling of paramagnetic austenite-ferromagnetic martensite transformation coupled with mechanics and micromagnetics
• High electrical conductivity in the epitaxial polar metals LaAuGe and LaPtSb
• Lattice-mediated bulk flexoelectricity from first principles