Nanoscale domain engineering in SrRuO$_3$ thin films

TL;DR

This study demonstrates nanoscale domain engineering in SrRuO$_3$/PbTiO$_3$/SrRuO$_3$ heterostructures, revealing how ferroelectric layer thickness influences domain propagation and structural modulation in epitaxial thin films.

Contribution

It introduces a method to control nanoscale domains via epitaxial coupling in heterostructures with variable ferroelectric layer thickness.

Findings

Structural distortions propagate through SrRuO$_3$ layers above a critical ferroelectric thickness.

Nanoscale domains can be engineered by tuning ferroelectric layer thickness.

Modulated structures extend beyond ferroelectric boundaries.

Abstract

We investigate nanoscale domain engineering via epitaxial coupling in a set of SrRuO$_3$/PbTiO$_3$/SrRuO$_3$ heterostructures epitaxially grown on (110)$_o$-oriented DyScO$_3$ substrates. The SrRuO$_3$ layer thickness is kept at 55 unit cells, whereas the PbTiO$_3$ layer is grown to thicknesses of 23, 45 and 90 unit cells. Through a combination of atomic force microscopy, x-ray diffraction and high resolution scanning transmission electron microscopy studies, we find that above a certain critical thickness of the ferroelectric layer, the large structural distortions associated with the ferroelastic domains propagate through the top SrRuO$_3$ layer, locally modifying the orientation of the orthorhombic SrRuO$_3$ and creating a modulated structure that extends beyond the ferroelectric layer boundaries.