Self-Compensating Incorporation of Mn in Ga_1-xMn_xAs

Abstract

A CT A P HY SIC A P O LO N IC A ANo . 3 P r oceedi n gs of t h e XXX I n t ern at io n al Sch oo l o f Sem icond uct i ng Co m p ou n ds, Ja szo wi ec 200 1Self-C om p en sat in g In corp oration of Mn in G a 1À x Mn x As J. M aç sek and F. M Ç acaIn st i t ut e of Ph ysi cs, Ac ademy of Sciences of the Czech R epu bl i c Na Slo vance 2, 182 21 P ra ha 8, Czech Republ i c W e consi der hyp othetic al Ga 7 Mn A s8 ; Ga 1 6 MnA s16 ; and Ga 1 4 Mn 3 A s16 crystals w ith Mn in a substitutio nal , interstitial, and both positio ns. Spin --p olari zed full-poten tial lineari zed au gmented plane w ave calculatio ns were used to obtain their electronic structure. W e show that the interstitial Mn

High Temperature Ferromagnetism and Nano-Scale Phase Separations in Diluted Magnetic Semiconductors and Oxides

“…These materials exhibit characteristics specific to both charge transfer insulators and strongly correlated disordered metals. Moreover, complexities specific to strongly correlated systems coexist in DMS with features exhibited by heavily doped semiconductors and semiconductor alloys, such as the Anderson-Mott localization [9], defect generation by self-compensation mechanisms [46,65,66], and the breakdown of the virtual crystal approximation [67]. Nevertheless, the theory built on p−d Zener model of carrier-mediated ferromagnetism and on either Kohn-Luttinger's kp [64,65,68] or multi-orbital tight-binding [69][70][71] descriptions of the valence band in tetrahedrally coordinated semiconductors has qualitatively, and often quantitatively, described thermodynamic, micromagnetic, transport, and optical properties of DMS with delocalized holes [72][73][74], challenging competing theories.…”

Cross-sectional scanning tunneling microscopy of Mn-doped GaAs: Theory and experiment

“…For filled state imaging, the upper bound of this energy range is the Fermi level. The Mn-doped GaAs sample under consideration in this work is p type with an estimated hole density of 10 19 cm Ϫ3 , so that the Fermi level should be near the valence-band maximum ͑VBM͒. Since we do not know the distribution of donors and acceptors present in the sample, this information alone is not sufficient to determine the exact location of the Fermi level for our sample.…”

Lattice constant in diluted magnetic semiconductors (Ga,Mn)As

“…Only recently it was suggested [5,6] and experimentally proved [7] that a portion of Mn occupies interstitial rather than substitutional positions in the zinc-blende lattice of (Ga,Mn)As. The interstitial Mn atoms act as double donors [5,6,8,9], in contrast to Mn atoms in the substitutional positions that are known to be acceptors.Almost unnoticed remains the surprising fact that the lattice constant of (Ga,Mn)As increases with increasing concentration of Mn [10]. According to the atomic radii [11], Mn atoms are smaller (R Mn = 1.17Å) than Ga atoms (R Ga = 1.25Å) and, in the simplest approximation, the lattice constant should be expected to decrease rather than to increase.…”