A route to room temperature ferromagnetic ultrathin SrRuO$_3$ films

TL;DR

This paper explores the challenge of stabilizing ferromagnetism in ultrathin SrRuO₃ films, using advanced theoretical methods to propose charge doping as a way to achieve room temperature ferromagnetism.

Contribution

It demonstrates that standard techniques cannot realize ultrathin ferromagnetic SrRuO₃ films and proposes charge doping as a novel method to induce room temperature ferromagnetism.

Findings

Intrinsic thickness limit for ferromagnetism in SrRuO₃

Standard thin-film techniques are insufficient for ultrathin ferromagnetic films

Charge doping can induce room temperature ferromagnetism in ultrathin SrRuO₃

Abstract

Experimental efforts to stabilize ferromagnetism in ultrathin films of transition metal oxides have so far failed, despite expectations based on density functional theory (DFT) and DFT+U. Here, we investigate one of the most promising materials, SrRuO$_3$, and include correlation effects beyond DFT by means of dynamical mean field theory. In agreement with experiment we find an intrinsic thickness limitation for metallic ferromagnetism in SrRuO$_3$ thin films. Indeed, we demonstrate that the realization of ultrathin ferromagnetic films is out of reach of standard thin-film techniques. Proposing charge carrier doping as a new route to manipulate thin films, we predict room temperature ferromagnetism in electron-doped SrRuO$_3$ ultra thin films.