Ee. Mitchell et al., HALL MEASUREMENTS OF THE INSULATING PHASES AT NU=1.5 AND NU-SIMILAR-TO-0.5 IN P-TYPE SI SI1-XCEX HETEROSTRUCTURES USING PULSED MAGNETIC-FIELDS/, Physica. B, Condensed matter, 246, 1998, pp. 391-394
Low temperature (0.3 K) Hall resistivities (rho(xy)) of the two dimens
ional hole system in high quality p-type Si/Si1-xGex single heterojunc
tions have been measured in pulsed magnetic fields to 50 T. Clean Hall
measurements are obtained by subtracting the raw signals from four se
parate field pulses. Hall data are presented in the Landau level filli
ng factor regime upsilon = 1.5 where we have previously identified an
insulating phase (IP). This IF, characterised by a rapid increase in r
ho(xx) as T --> 0 K and non-linear I-V measurements, is shown to incre
ase at large tilt angles. The corresponding Hall resistivity in the IP
region, measured in tilted pulsed magnetic fields, remains finite and
close to the classical value. Preliminary pulsed magneto-transport re
sults are presented for a second IP which indicate that both rho(xx) a
nd rho(xy) increase dramatically for upsilon < 0.5. (C) 1998 Elsevier
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