arXiv subjects

Ryan Snow

Publications and source records attributed to Ryan Snow.

2 recordsLinked to original sources

arXiv2009

Studies of single doping of Mn and Fe in Si to deduce simple guidelines in selecting transition metal elements for growing Si-based spintronic materials

Single dopings of Mn and Fe in Si are investigated using 8-, 64-, and 216-atom supercells and a first-principles method based on density functional theory. Between the two transition metal elements (TMEs), atom sizes play an essential role in determining the contraction or the expansion of neighboring atoms around the TME dopant at a substitutional site. At a tetrahedral interstitial site, there is only expansion. Magnetic moments/TME at the two sites are calculated. Physical origins for these inter-related properties are discussed. A few suggestions about the growth of these Si-based alloys are given.

cond-mat.mtrl-sci↗

arXiv2009

Origin of large moments in Mn$_x$Si$_{1-x}$ at small x

Recently, the magnetic moment/Mn, $M$, in Mn$_x$Si$_{1-x}$ was measured to be 5.0 $\mu_B$/Mn, at $x$ =0.1%. To understand this observed $M$, we investigate several Mn$_x$Si$_{1-x}$ models of alloys using first-principles density functional methods. The only model giving $M = 5.0$ was a 513-atom cell having the Mn at a substitutional site, and Si at a second-neighbor interstitial site. The observed large moment is a consequence of the weakened d-p hybridization between the Mn and one of its nearest neighbor Si atoms, resulting from the introduction of the second-neighbor interstitial Si. Our result suggests a way to tune the magnetic moments of transition metal doped semiconductors.

cond-mat.mtrl-sci↗