Structural, electronic and magnetic properties of Mn, Co, Ni in Ge n for ( n=1–13)

• Published in: Physica. B, Condensed matter Vol. 406; no. 24; pp. 4612 - 4619
• Main Authors: Kapila, Neha, Jindal, V.K., Sharma, Hitesh
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-12-2011
• Subjects: Density functional theory; Doped germanium clusters; Magnetic semiconductors; Density functional theory; Doped germanium clusters; Magnetic semiconductors
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2011.09.038

The structural, electronic and magnetic properties of TMGe
n
(TM=Mn, Co, Ni;
n=1–13) have been investigated using spin polarized density functional theory. The transition metal (TM) atom prefers to occupy surface positions for
n
<
9
and endohedral positions for
n
≥
9
. The critical size of the cluster to form endohedral complexes is at
n=9, 10 and 11 for Mn, Co and Ni respectively. The binding energy of TMGe
n
clusters increases with increase in cluster size. The Ni doped Ge
n
clusters have shown higher stability as compared to Mn and Co doped Ge
n
clusters. The HOMO–LUMO gap for spin up and down electronic states of Ge
n
clusters is found to change significantly on TM doping. The magnetic moment in TMGe
n
is introduced due to the presence of TM. The magnetic moment is mainly localized at the TM site and neighbouring Ge atoms. The magnetic moment is quenched in NiGe
n
clusters for all
n except for
n=2, 4 and 8.