Antiferrodistortive and Ferroeletric Phase Transitions in Freestanding Films of SrTiO<sub>3</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40310519.
- Also identified by DOI 10.1021/acs.nanolett.4c05664 and PMC identifier 12082687.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Thin films' properties can be greatly influenced by their supporting growth substrates. Even in the so-called strain-free heterostructure films, it is still unclear whether there will be no interfacial electronic reconstructions induced by the underlying substrates. Here, we report the studies of SrTiO<sub>3</sub> (STO) films in the freestanding form (FS) with a thickness ranging from 20 to 80 nm. These STO films, by default, are in a strain-free state; they exhibit distinct properties not seen in both bulk and strain-free heterostructure forms. Our films show an enhanced antiferrodistortive (AFD) phase transition temperature with a preferential in-plane rotation axis for the TiO<sub>6</sub> octahedra. The anisotropic Ti orbital occupancy around the surface signals the departure of its properties from the bulk. Moreover, we have found that the in-plane ferroelectricity can be strengthened by the reduced dimensionality, establishing that the dimensionality control is an important factor for enhancing STO's ferroelectric response.