Tuning the Magnetic and Electronic Properties of Strontium Titanate by Carbon Doping

TL;DR

This study uses first-principles calculations to show how carbon doping in strontium titanate can tune its magnetic and electronic properties, depending on dopant configuration and distance.

Contribution

It reveals the dependence of magnetic and electronic properties of C-doped SrTiO3 on dopant configuration and introduces ways to tailor these properties for applications.

Findings

C dopants form stable structures with nonmagnetic features when nearest neighbors.

Increasing C-C distance induces transitions from nonmagnetic metal to magnetic semiconductors.

Doping configurations can be used to engineer magnetic and electronic behaviors in SrTiO3.

Abstract

The magnetic and electronic properties of strontium titanate with different carbon dopant configurations are explored using first-principles calculations with a generalized gradient approximation (GGA) and the GGA+U approach. Our results show that the structural stability, electronic properties and magnetic properties of C-doped SrTiO3 strongly depend on the distance between carbon dopants. In both GGA and GGA+U calculations, the doping structure is mostly stable with a nonmagnetic feature when the carbon dopants are nearest neighbors, which can be ascribed to the formation of a C-C dimer pair accompanied by stronger C-C and weaker C-Ti hybridizations as the C-C distance becomes smaller. As the C-C distance increases, C-doped SrTiO3 changes from an n-type nonmagnetic metal to ferromagnetic/antiferromagnetic half-metal and to an antiferromagnetic/ferromagnetic semiconductor in GGA calculations, while it changes from a nonmagnetic semiconductor to ferromagnetic half-metal and to an antiferromagnetic semiconductor using the GGA+U method. Our work demonstrates the possibility of tailoring the magnetic and electronic properties of C-doped SrTiO3, which might provide some guidance to extend the applications of strontium titanate as a magnetic or optoelectronic material.