Route to room-temperature ferromagnetic ultrathin SrRuO₃ films

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, SrRuO3, 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 SrRuO3 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 an alternative route to manipulate thin films, we predict room-temperature ferromagnetism in electron-doped SrRuO3 ultrathin films.