Band structure evolution and the origin of magnetism in (Ga,Mn)As : From paramagnetic through superparamagnetic to ferromagnetic phase
(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
- Gluba, L. ; Yastrubchak, O. ; Domagala, J. Z. ; Jakiela, R. ; Andrearczyk, T. ; Zuk, J. ; Wosinski, T. ; Sadowski, J. LU and Sawicki, M.
- organization
- publishing date
- 2018-03-13
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Review B
- volume
- 97
- issue
- 11
- article number
- 115201
- 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
- 2023-03-23 10:09:08
@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>}}, 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}}, doi = {{10.1103/PhysRevB.97.115201}}, volume = {{97}}, year = {{2018}}, }