Tailoring strain in SrTiO3 compound by low energy He+ irradiation

TL;DR

This paper demonstrates how low energy He+ ion irradiation can controllably induce strain in the near-surface layer of SrTiO3, achieving significant distortions without amorphisation.

Contribution

It introduces a method to tailor lattice strain in SrTiO3 using low energy helium ion irradiation, with detailed analysis of strain distribution and effects.

Findings

Strain distribution extends up to 200 nm from surface.

Maximum distortions of 5-7% achieved without amorphisation.

Perpendicular expansion observed due to substrate clamping.

Abstract

The ability to generate a change of the lattice parameter in a near-surface layer of a controllable thickness by ion implantation of strontium titanate is reported here using low energy He+ ions. The induced strain follows a distribution within a typical near-surface layer of 200 nm as obtained from structural analysis. Due to clamping effect from the underlying layer, only perpendicular expansion is observed. Maximum distortions up to 5-7% are obtained with no evidence of amorphisation at fluences of 1E16 He+ ions/cm2 and ion energies in the range 10-30 keV.