Imperial College London
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Professor Lesley F Cohen

Faculty of Natural Sciences, Department of Physics

Associate Provost (Equality, Diversity and Inclusion)
 
 
 
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Contact

 

+44 (0)20 7594 7598l.cohen Website CV

 
 
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Assistant

 

Mrs Carolyn Dale +44 (0)20 7594 7579

 
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Location

 

1111Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Ferreira-Teixeira:2022:10.1021/acsaelm.2c00966,
author = {Ferreira-Teixeira, S and Vanstone, A and Pires, AL and Branford, WR and Arafijo, JP and Cohen, LF and Pereira, AM},
doi = {10.1021/acsaelm.2c00966},
journal = {Physical Review B: Condensed Matter and Materials Physics},
pages = {5789--5798},
title = {Electronic conduction channels engineered in topological insulator sputtered thin films},
url = {http://dx.doi.org/10.1021/acsaelm.2c00966},
volume = {4},
year = {2022}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Sb2Te3 is a topological insulator (TI) material that can be used in a wide range of applications from energy harvesting to Spin-Orbitronics. In this paper, the structural, electrical, and thermal transport properties of nanocrystalline ion beam sputtered Sb2Te3 thin films were studied. Films with thicknesses between 35 and 300 nm, with nanocrystallites of sizes 10–20 nm, have a high resistivity between 0.072 and 2.03 Ω cm at 300 K, increasing with cooling. The Seebeck coefficient demonstrates the coexistence of n-type and p-type conduction, the latter being more prominent at high temperatures and in thicker films. The morphological and transport properties reveal that the films are constituted by two layers having different majority charge carriers, with the electronic bulk conduction being described by two semiconductor layers conducting in parallel, one p-type at the surface and another n-type, each described by an activation energy-dependent conductivity. Besides these bulk contributions, weak antilocalization (WAL) cusps are observed in the magnetoconductance below 10 K and at low magnetic fields. Analysis of the WAL hints that there is one two-dimensional conduction channel open at low temperatures for the thinner films, whereas for the thicker film, this 2D conduction appears to be masked by the bulk channels. However, a magnetic localization length LΦ between 62 and 90 nm at 2 K is observed for all thin films. This behavior suggests that as the bulk activation energy conductions freeze out at low temperatures, the electrical conduction is carried by the supposed 2D state, which appears to have some of the features of a TI surface state. Through these measurements, we demonstrate that the type of dominant conduction can be controlled by the Sb2Te3 film thickness in these large area sputtered films, while the conduction at low temperatures appears to be dominated by a robust TI state.
AU  - Ferreira-Teixeira,S
AU  - Vanstone,A
AU  - Pires,AL
AU  - Branford,WR
AU  - Arafijo,JP
AU  - Cohen,LF
AU  - Pereira,AM
DO  - 10.1021/acsaelm.2c00966
EP  - 5798
PY  - 2022///
SN  - 1098-0121
SP  - 5789
TI  - Electronic conduction channels engineered in topological insulator sputtered thin films
T2  - Physical Review B: Condensed Matter and Materials Physics
UR  - http://dx.doi.org/10.1021/acsaelm.2c00966
UR  - http://hdl.handle.net/10044/1/101964
VL  - 4
ER  -
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