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MnAs dots grown on GaN( 000(1)over-bar)-(1x1) surface

Kowalik, I. A.; Kowalski, B. J.; Iwanowski, R. J.; Kopalko, K.; Lusakowska, E.; Sawicki, M.; Sadowski, Janusz LU ; Adell, M.; Grzegory, I. and Porowski, S. (2007) In Physical Review B (Condensed Matter and Materials Physics) 75(23).
Abstract
MnAs has been grown by means of MBE on the GaN(000 (1) over bar)-(1x1) surface. Two options of initiating the crystal growth were applied: (a) a regular MBE procedure (manganese and arsenic were delivered simultaneously) and (b) subsequent deposition of manganese and arsenic layers. It was shown that spontaneous formation of MnAs dots with the surface density of 1x10(11) cm(-2) and 2.5x10(11) cm(-2), respectively (as observed by atomic force microscopy), occurred for the layer thickness higher than 5 ML. Electronic structure of the MnAs/GaN systems was studied by resonant photoemission spectroscopy. That led to determination of the Mn 3d-related contribution to the total density of states distribution of MnAs. It has been proven that the... (More)
MnAs has been grown by means of MBE on the GaN(000 (1) over bar)-(1x1) surface. Two options of initiating the crystal growth were applied: (a) a regular MBE procedure (manganese and arsenic were delivered simultaneously) and (b) subsequent deposition of manganese and arsenic layers. It was shown that spontaneous formation of MnAs dots with the surface density of 1x10(11) cm(-2) and 2.5x10(11) cm(-2), respectively (as observed by atomic force microscopy), occurred for the layer thickness higher than 5 ML. Electronic structure of the MnAs/GaN systems was studied by resonant photoemission spectroscopy. That led to determination of the Mn 3d-related contribution to the total density of states distribution of MnAs. It has been proven that the electronic structures of the MnAs dots grown by the two procedures differ markedly. One corresponds to metallic, ferromagnetic NiAs-type MnAs, the other is similar to that reported for half-metallic zinc-blende MnAs. Both systems behave superparamagnetically (as revealed by magnetization measurements), but with both the blocking temperatures and the intradot Curie temperatures substantially different. The intradot Curie temperature is about 260 K for the former system while markedly higher than room temperature for the latter one. Relations between growth process, electronic structure, and other properties of the studied systems are discussed. Possible mechanisms of half-metallic MnAs formation on GaN are considered. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
75
issue
23
publisher
American Physical Society
external identifiers
  • wos:000247624900075
  • scopus:34347391704
ISSN
1098-0121
DOI
10.1103/PhysRevB.75.235303
language
English
LU publication?
yes
id
01725322-dd3a-4f0a-8a83-e0603e90b0c8 (old id 646208)
date added to LUP
2007-12-12 09:26:35
date last changed
2017-01-01 07:06:49
@article{01725322-dd3a-4f0a-8a83-e0603e90b0c8,
  abstract     = {MnAs has been grown by means of MBE on the GaN(000 (1) over bar)-(1x1) surface. Two options of initiating the crystal growth were applied: (a) a regular MBE procedure (manganese and arsenic were delivered simultaneously) and (b) subsequent deposition of manganese and arsenic layers. It was shown that spontaneous formation of MnAs dots with the surface density of 1x10(11) cm(-2) and 2.5x10(11) cm(-2), respectively (as observed by atomic force microscopy), occurred for the layer thickness higher than 5 ML. Electronic structure of the MnAs/GaN systems was studied by resonant photoemission spectroscopy. That led to determination of the Mn 3d-related contribution to the total density of states distribution of MnAs. It has been proven that the electronic structures of the MnAs dots grown by the two procedures differ markedly. One corresponds to metallic, ferromagnetic NiAs-type MnAs, the other is similar to that reported for half-metallic zinc-blende MnAs. Both systems behave superparamagnetically (as revealed by magnetization measurements), but with both the blocking temperatures and the intradot Curie temperatures substantially different. The intradot Curie temperature is about 260 K for the former system while markedly higher than room temperature for the latter one. Relations between growth process, electronic structure, and other properties of the studied systems are discussed. Possible mechanisms of half-metallic MnAs formation on GaN are considered.},
  author       = {Kowalik, I. A. and Kowalski, B. J. and Iwanowski, R. J. and Kopalko, K. and Lusakowska, E. and Sawicki, M. and Sadowski, Janusz and Adell, M. and Grzegory, I. and Porowski, S.},
  issn         = {1098-0121},
  language     = {eng},
  number       = {23},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {MnAs dots grown on GaN( 000(1)over-bar)-(1x1) surface},
  url          = {http://dx.doi.org/10.1103/PhysRevB.75.235303},
  volume       = {75},
  year         = {2007},
}