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Electron Assisted Variable Range Hopping in Strongly Correlated 2D Electron Systems
Author(s) -
Ghosh A.,
Pepper M.,
Ritchie D. A.,
Linfield E. H.,
Harrell R. H.,
Beere H. E.,
Jones G. A. C.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200203)230:1<211::aid-pssb211>3.0.co;2-n
Subject(s) - variable range hopping , electrical resistivity and conductivity , electron , oscillation (cell signaling) , condensed matter physics , range (aeronautics) , activation energy , physics , materials science , chemistry , quantum mechanics , biochemistry , composite material , organic chemistry
We have investigated the temperature dependence of longitudinal resistivity of high mobility two dimensional (2D) electron systems in the strongly correlated regime ( r s ∼ 4–5). The area of the samples was relatively small, typically 2 × 2 μm 2 . The resistivity followed an Efros–Shklovskii (ES)‐type variable range hopping (VRH) behavior, ϱ ( T ) = ϱ 0 exp ( T 0 / T ) p , with p = 0.5. We found that in this regime, the pre‐factor ϱ 0 increases by discrete steps of h /2 e 2 as the carrier concentration ( n ) is increased, starting from ϱ 0 = h / e 2 at the lowest values of n close to the localization. The jumps in ϱ 0 were associated with an oscillation in the activation energy defined by T 0 . We have discussed the observation of such quantized, temperature‐independent resistivity pre‐factors in the framework of electron assisted VRH.