Promising strategy leverages atomic displacements to control quantum properties of a vanadate perovskite

Perovskites, materials with a crystal structure that mirrors that of the mineral calcium titanate CaTiO₃, exhibit properties that are advantageous for developing various technologies. For instance, they have proved promising for designing photovoltaic (PV) systems and electronic devices.

Perovskites are also ideal materials to explore a variety of quantum states, including orbital order, magnetism and superconductivity. Moreover, physicists can carefully engineer these materials to unlock various tunable properties, which typically result from subtle deviations from the cubic perovskite structure.

Realizing these deviations and controlling them to attain specific properties can be highly challenging. In a recent paper published in Nature Physics, researchers at the Max Planck Institute for Solid State Research introduced a promising strategy to realize subtle atomic displacements in the vanadate perovskite YVO₃.

“The objective of our recent study was to gain a fundamental understanding of how the functional properties of a crystalline material change when it is grown as a thin film in an oriented manner on different facets of another crystal, while control parameters such as lattice and polarity mismatch with the film remain almost unchanged,” Eva Benckiser, senior author of the paper, told Phys.org.

To directionally imprint slight atomic displacements in the antiferromagnetic Mott insulator YVO₃, the researchers deposited epitaxial films on different facets of the same substrate. Notably, they observed that the vanadate films on different facets of the substrate exhibited distinct spin-orbital ordering patterns.

“In materials with strong electron-electron correlations, such as the perovskite vanadate YVO₃, the physical properties are very sensitive to the smallest structural changes, such as those that occur at interfaces when materials with different crystal lattices grow together,” explained Benckiser.

“In the present work, we used two cuts of an orthorhombic substrate material, YAlO₃, which have facets that are indistinguishable in the cubic reference system and have a very similar lattice mismatch with YVO₃.”

The recent study by Benckiser and her colleagues demonstrates that substrate facets could be leveraged to carefully tailor the spin-orbital behavior of perovskites. Initial experiments highlight the promise of their proposed approach, which could eventually be used to design new materials for various technologies.

“Our light scattering experiments show that the magnetic ordering patterns are different depending on the substrate facet and that this is due to the subtle difference in the atomic displacements imprinted at the substrate-film interface,” said Benckiser. “This fundamental effect can be used to stabilize desired phases in various functional perovskite materials, for example, to create novel spintronic materials.”

The researchers hope their recent work will contribute to the precise engineering of quantum materials, offering physicists an alternative route for manipulating their properties. Meanwhile, they plan to continue building on the approach they devised while also exploring the extent to which imprinted displacement patterns affect the properties of other perovskites.

“In the future, we plan to investigate the length scale of the imprinted orthorhombic displacements in more detail and to explore the influence of different facets in other functional perovskite thin films,” added Benckiser.

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