Growth of (Ge,Mn) nanocolumns on GaAs(100): the role of morphology and co-doping on magnetotransport

Matthieu Jamet (1) , Ing-Song Yu (1) , Thibaut Devillers (1) , André Barski (1) , Pascale Bayle-Guillemaud (1) , Cyrille Beigne (1) , Johan Rothman (2) , Vincent Baltz (3) , Joel Cibert (4)

1 SP2M - UMR 9002 - Service de Physique des Matériaux et Microstructures
2 DOPT - Département d'Optronique
3 SPINTEC - SPINtronique et TEchnologie des Composants
4 NEEL - NPSC - Nanophysique et Semiconducteurs

Changing the morphology of the growing surface and the nature of residual impurities in (Ge,Mn) layers - by using different substrates - dramatically changes the morphology of the ferromagnetic Mn-rich inclusions and the magnetotransport properties. We obtained p-type layers with nanocolumns, either parallel or entangled, and n-type layers with spherical clusters. Holes exhibit an anomalous Hall effect, and electrons exhibit a tunneling magnetoresistance, both with a clear dependence on the magnetization of the Mn-rich inclusions; holes exhibit orbital MR, and electrons show only the normal Hall effect, and an additional component of magnetoresistance due to weak localization, all three being independent of the magnetic state of the Mn rich inclusions. Identified mechanisms point to the position of the Fermi level of the Mn-rich material with respect to the valence band of germanium as a crucial parameter in such hybrid layers.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Matthieu Jamet, Ing-Song Yu, Thibaut Devillers, André Barski, Pascale Bayle-Guillemaud, et al.. Growth of (Ge,Mn) nanocolumns on GaAs(100): the role of morphology and co-doping on magnetotransport. 2009. ⟨hal-00426822⟩