Theoretical investigation on the magnetic phase stability of Fe-doped Bi tellurides

The structural properties and magnetic phase stability of Fe-doped Bi2Te3 are studied in first principles by means of the highly precise full-potential linearized augmented plane-wave method within the generalized gradient approximation. Two different types of Fe doping, which are substitutional and interstitial, are examined, assuming about 8% of the Fe doping level, where the atomic structures are fully optimized by atomic force calculations. Our results show that: (i) ferromagnetic phases are energetically more stable over paramagnetic phases for both substitutional and interstitial Fe dopings, (ii) the substitutional Fe doping indicates a high magnetic phase with a largely enhanced Fe magnetic moment of 3.40 mu(B) while the interstitial Fe doping shows the magnetic moment similar to the Fe bulk value, and (iii) the structural optimization reduces the Fe magnetic moments for both doping types while the overall effects on the total moment exhibit different results for different doping types. (C) 2012 American Institute of Physics. [doi:10.1063/1.3671777]