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Band structure evolution and the origin of magnetism in (Ga,Mn)As : From paramagnetic through superparamagnetic to ferromagnetic phase

Gluba, L.; Yastrubchak, O.; Domagala, J. Z.; Jakiela, R.; Andrearczyk, T.; Zuk, J.; Wosinski, T.; Sadowski, J. LU and Sawicki, M. (2018) In Physical Review B 97(11).
Abstract

The high-spectral-resolution optical studies of the energy gap evolution, supplemented with electronic, magnetic, and structural characterization, show that the modification of the GaAs valence band caused by Mn incorporation occurs already for a very low Mn content, much lower than that required to support ferromagnetic spin-spin coupling in (Ga,Mn)As. Only for n-type (Ga,Mn)As with the Mn content below about 0.3% the Mn-related extended states are visible as a feature detached from the valence-band edge and partly occupied with electrons. The combined magnetic and low-temperature photoreflectance studies presented here indicate that the paramagnetic ↔ ferromagnetic transformation in p-type (Ga,Mn)As takes place without imposing... (More)

The high-spectral-resolution optical studies of the energy gap evolution, supplemented with electronic, magnetic, and structural characterization, show that the modification of the GaAs valence band caused by Mn incorporation occurs already for a very low Mn content, much lower than that required to support ferromagnetic spin-spin coupling in (Ga,Mn)As. Only for n-type (Ga,Mn)As with the Mn content below about 0.3% the Mn-related extended states are visible as a feature detached from the valence-band edge and partly occupied with electrons. The combined magnetic and low-temperature photoreflectance studies presented here indicate that the paramagnetic ↔ ferromagnetic transformation in p-type (Ga,Mn)As takes place without imposing changes of the unitary character of the valence band with the Fermi level located therein. The whole process is rooted in the nanoscale fluctuations of the local (hole) density of states and the formation of a superparamagnetic-like state. The Fermi level in (Ga,Mn)As is coarsened by the carrier concentration of the itinerant valence band holes and further fine-tuned by the many-body interactions.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
97
issue
11
publisher
American Physical Society
external identifiers
  • scopus:85044001007
ISSN
2469-9950
DOI
10.1103/PhysRevB.97.115201
language
English
LU publication?
yes
id
d450d9ef-118c-4edd-861d-ef17815acdb6
date added to LUP
2018-03-29 08:41:50
date last changed
2018-10-03 12:07:26
@article{d450d9ef-118c-4edd-861d-ef17815acdb6,
  abstract     = {<p>The high-spectral-resolution optical studies of the energy gap evolution, supplemented with electronic, magnetic, and structural characterization, show that the modification of the GaAs valence band caused by Mn incorporation occurs already for a very low Mn content, much lower than that required to support ferromagnetic spin-spin coupling in (Ga,Mn)As. Only for n-type (Ga,Mn)As with the Mn content below about 0.3% the Mn-related extended states are visible as a feature detached from the valence-band edge and partly occupied with electrons. The combined magnetic and low-temperature photoreflectance studies presented here indicate that the paramagnetic ↔ ferromagnetic transformation in p-type (Ga,Mn)As takes place without imposing changes of the unitary character of the valence band with the Fermi level located therein. The whole process is rooted in the nanoscale fluctuations of the local (hole) density of states and the formation of a superparamagnetic-like state. The Fermi level in (Ga,Mn)As is coarsened by the carrier concentration of the itinerant valence band holes and further fine-tuned by the many-body interactions.</p>},
  articleno    = {115201},
  author       = {Gluba, L. and Yastrubchak, O. and Domagala, J. Z. and Jakiela, R. and Andrearczyk, T. and Zuk, J. and Wosinski, T. and Sadowski, J. and Sawicki, M.},
  issn         = {2469-9950},
  language     = {eng},
  month        = {03},
  number       = {11},
  publisher    = {American Physical Society},
  series       = {Physical Review B},
  title        = {Band structure evolution and the origin of magnetism in (Ga,Mn)As : From paramagnetic through superparamagnetic to ferromagnetic phase},
  url          = {http://dx.doi.org/10.1103/PhysRevB.97.115201},
  volume       = {97},
  year         = {2018},
}