Resistance noise in epitaxial thin films of ferromagnetic topological insulators
Abstract
We report detailed temperature and gate-voltage dependence of 1/f resistance noise in magnetically doped topological insulators (TI) Crx(Bi,Sb)2−xTe3. The noise is remarkably sensitive to the gate voltage, increasing rapidly as the chemical potential is moved towards the charge neutrality point. Unlike in identically prepared (Bi,Sb)2Te3 films, where mobility-fluctuations in the surface states is the dominant mechanism, the noise in the magnetic Crx(Bi,Sb)2−xTe3 originates from transport in the localized band tail of the bulk valence band. A strong increase in noise with decreasing temperature supports this scenario. At higher temperature (≥10 K), we observed large noise peaks at gate voltage-dependent characteristic temperature scales. In line with similar observations in other non-magnetic TI systems, we attribute these peaks to generation-recombination in the Cr-impurity band.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 22, 2016
- Source ID
- 10.1063/1.4942412
Entities
People
- Abhinav Kandala
- Anthony Richardella
- Arindam Ghosh
- Nitin Samarth
- Saurav Islam
- Semonti Bhattacharyya
Organizations
- Council of Scientific and Industrial Research
- Indian Institute of Science, Bengaluru
- International Business Machines Corporation (Armonk, NY)
- Office of Naval Research
- Pennsylvania State University