TY - JOUR
T1 - Resistance noise in epitaxial thin films of ferromagnetic topological insulators
AU - Bhattacharyya, Semonti
AU - Kandala, Abhinav
AU - Richardella, Anthony
AU - Islam, Saurav
AU - Samarth, Nitin
AU - Ghosh, Arindam
N1 - Funding Information:
The sample growth and characterization effort at Penn State was supported by ONR Grant No. N0014-15-1-2370. S.B. thanks CSIR for senior research fellowship
PY - 2016/2/22
Y1 - 2016/2/22
N2 - 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.
AB - 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.
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U2 - 10.1063/1.4942412
DO - 10.1063/1.4942412
M3 - Article
AN - SCOPUS:85020190383
SN - 0003-6951
VL - 108
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 8
M1 - 082101
ER -