Electronic localization on the structural inhomogeneities formed due to Bi and Te deficiency in the MBE grown films of AF topological insulator MnBi2Te4: evidence from spectroscopic ellipsometry and infrared studies
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F25%3A00642486" target="_blank" >RIV/68378271:_____/25:00642486 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.1063/5.0288900" target="_blank" >https://doi.org/10.1063/5.0288900</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1063/5.0288900" target="_blank" >10.1063/5.0288900</a>
Alternative languages
Result language
angličtina
Original language name
Electronic localization on the structural inhomogeneities formed due to Bi and Te deficiency in the MBE grown films of AF topological insulator MnBi2Te4: evidence from spectroscopic ellipsometry and infrared studies
Original language description
The intrinsic substitutional and antisite defects cause unintentional doping and a shift of the E-F position above the conduction band minimum in the AF topological insulator MnBi2Te4. This prevents measurements of the quantum anomalous Hall effect and the investigation of the topological Dirac states. In the present study, the Mn-Bi-Te films grown by the MBE technique onto Si(111) substrates with decreasing Bi and Te contents and increasing Mn content were investigated by 0.5-6.5 eV spectroscopic ellipsometry. In addition, the 0.004-0.9 eV infrared transmittance spectra were examined. An effective medium model was used to reproduce the measured ellipsometric angles, Psi(omega) and Delta(omega), of the Mn-Bi-Te films in terms of the constructed model, including film thickness, surface roughness, and volume fractions of two (MnTe and Bi2Te3) or three constituents, the latter being associated with the structural inhomogeneities contribution. The results obtained for the inhomogeneous Mn-Bi-Te films using the three-phase effective medium approximation model reveal that the defect-associated optical response systematically shifts to higher photon energies from similar to 1.95 to similar to 2.43 eV with decreasing Te and Bi contents and increasing Mn content, indicating that the electrons become more deeply localized in the formed structural inhomogeneities. The obtained results indicate that the structure of the non-stoichiometric Mn-Bi-Te films is not continuous but represented by regions of a nearly stoichiometric MnBi2Te4 phase, which includes hollows or quantum anti-dots. The measured far-infrared transmittance spectra for the non-stoichiometric Mn-Bi-Te films show substantially reduced (or absent) contributions from free charge carriers, which supports the relevance of localization effects.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Chemical Physics
ISSN
0021-9606
e-ISSN
1089-7690
Volume of the periodical
163
Issue of the periodical within the volume
19
Country of publishing house
US - UNITED STATES
Number of pages
10
Pages from-to
194711
UT code for WoS article
001620727000005
EID of the result in the Scopus database
2-s2.0-105022521357