Hopping conduction in uniaxially stressed Si:B near the insulatormetal transition
Abstract
Using uniaxial stress to tune the critical density near that of the sample, we have studied in detail the lowtemperature conductivity of ptype Si:B in the insulating phase very near the metalinsulator transition. For all values of temperature and stress, the conductivity collapses onto a single universal curve, {sigma}(S,T)=AT{sup 1/2}F[T{sup {asterisk}}(S)/T]. For large values of the argument, the scaling function F[T{sup {asterisk}}(S)/T] is well fit by exp[{minus}(T{sup {asterisk}}/T){sup 1/2}], the exponentially activated form associated with variablerange hopping when electronelectron interactions cause a soft Coulomb gap in the density of states at the Fermi energy. The temperature dependence of the prefactor, corresponding to the T dependence of the critical curve, has been determined reliably for this system, and is {proportional_to}T{sup 0.5}. We show explicitly that neglecting the prefactor leads to substantial errors in the determination of the T{sup {asterisk}}{close_quote}s and the critical exponents derived from them. The conductivity is not consistent with Mott variablerange hopping, exp[{minus}(T{sup {asterisk}}/T){sup 1/4}], in the critical region, nor does it obey this form for any range of the parameters. Instead, the conductivity of Si:B is well fit by {sigma}=AT{sup 1/2}&hthinsp;exp[{minus}(T{sup {asterisk}}/T){sup {alpha}}] for smaller argument of the scaling function, with {alpha}=0.31 related to the critical exponentsmore »
 Authors:

 Physics Department, City College of the City University of New York, New York, New York 10031 (United States)
 Department of Electrical Engineering, Princeton University, Princeton, New Jersey 085445263 (United States)
 Publication Date:
 OSTI Identifier:
 357609
 Resource Type:
 Journal Article
 Journal Name:
 Physical Review, B: Condensed Matter
 Additional Journal Information:
 Journal Volume: 60; Journal Issue: 4; Other Information: PBD: Jul 1999
 Country of Publication:
 United States
 Language:
 English
 Subject:
 36 MATERIALS SCIENCE; BORON; FERMI LEVEL; SILICON; DOPED MATERIALS; BORON ADDITIONS; ELECTRIC CONDUCTIVITY; TEMPERATURE DEPENDENCE; STRESSES; SCALING; ELECTRONELECTRON INTERACTIONS; ENERGY GAP
Citation Formats
Bogdanovich, S, Simonian, D, Kravchenko, S V, Sarachik, M P, and Bhatt, R N. Hopping conduction in uniaxially stressed Si:B near the insulatormetal transition. United States: N. p., 1999.
Web. doi:10.1103/PhysRevB.60.2286.
Bogdanovich, S, Simonian, D, Kravchenko, S V, Sarachik, M P, & Bhatt, R N. Hopping conduction in uniaxially stressed Si:B near the insulatormetal transition. United States. doi:10.1103/PhysRevB.60.2286.
Bogdanovich, S, Simonian, D, Kravchenko, S V, Sarachik, M P, and Bhatt, R N. Thu .
"Hopping conduction in uniaxially stressed Si:B near the insulatormetal transition". United States. doi:10.1103/PhysRevB.60.2286.
@article{osti_357609,
title = {Hopping conduction in uniaxially stressed Si:B near the insulatormetal transition},
author = {Bogdanovich, S and Simonian, D and Kravchenko, S V and Sarachik, M P and Bhatt, R N},
abstractNote = {Using uniaxial stress to tune the critical density near that of the sample, we have studied in detail the lowtemperature conductivity of ptype Si:B in the insulating phase very near the metalinsulator transition. For all values of temperature and stress, the conductivity collapses onto a single universal curve, {sigma}(S,T)=AT{sup 1/2}F[T{sup {asterisk}}(S)/T]. For large values of the argument, the scaling function F[T{sup {asterisk}}(S)/T] is well fit by exp[{minus}(T{sup {asterisk}}/T){sup 1/2}], the exponentially activated form associated with variablerange hopping when electronelectron interactions cause a soft Coulomb gap in the density of states at the Fermi energy. The temperature dependence of the prefactor, corresponding to the T dependence of the critical curve, has been determined reliably for this system, and is {proportional_to}T{sup 0.5}. We show explicitly that neglecting the prefactor leads to substantial errors in the determination of the T{sup {asterisk}}{close_quote}s and the critical exponents derived from them. The conductivity is not consistent with Mott variablerange hopping, exp[{minus}(T{sup {asterisk}}/T){sup 1/4}], in the critical region, nor does it obey this form for any range of the parameters. Instead, the conductivity of Si:B is well fit by {sigma}=AT{sup 1/2}&hthinsp;exp[{minus}(T{sup {asterisk}}/T){sup {alpha}}] for smaller argument of the scaling function, with {alpha}=0.31 related to the critical exponents of the system at the metalinsulator transition. {copyright} {ital 1999} {ital The American Physical Society}},
doi = {10.1103/PhysRevB.60.2286},
journal = {Physical Review, B: Condensed Matter},
number = 4,
volume = 60,
place = {United States},
year = {1999},
month = {7}
}