Details
| Original language | English |
|---|---|
| Pages (from-to) | 108-111 |
| Number of pages | 4 |
| Journal | Surface science |
| Volume | 263 |
| Issue number | 1-3 |
| Publication status | Published - 19 Feb 1992 |
| Externally published | Yes |
Abstract
We have studied the magnetoresistance of AlGaAs/GaAs-heterojunctions at millikelvin temperatures in small Hall bar and Corbino geometries with different sizes. Below a characteristic temperature Tc which increases with decreasing sample width, the phase-breaking length Lin is larger than the sample size. Under these conditions the half width ΔB of the longitudinal magnetoresistance no longer depends upon temperature but only upon size. By varying the size it is thus possible to directly investigate the localization transition in the integer quantum Hall regime and to measure the critical exponent v of the localization length ξ α |B - Bc|-v. Our results show a universal behaviour in the three lowest Landau levels. This is in agreement w universality statement of the field-theoretic approach to the metal-insulator transition in the quantum Hall effect. By studying the characteristic temperature Tc for different widths, the temperature exponent p 2 of the inelastic scattering length can also be measured.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Materials Science(all)
- Surfaces, Coatings and Films
- Materials Science(all)
- Materials Chemistry
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In: Surface science, Vol. 263, No. 1-3, 19.02.1992, p. 108-111.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Direct measurement of critical exponents in the quantum Hall regime
AU - Koch, S.
AU - Haug, R. J.
AU - von Klitzing, K.
AU - Ploog, K.
PY - 1992/2/19
Y1 - 1992/2/19
N2 - We have studied the magnetoresistance of AlGaAs/GaAs-heterojunctions at millikelvin temperatures in small Hall bar and Corbino geometries with different sizes. Below a characteristic temperature Tc which increases with decreasing sample width, the phase-breaking length Lin is larger than the sample size. Under these conditions the half width ΔB of the longitudinal magnetoresistance no longer depends upon temperature but only upon size. By varying the size it is thus possible to directly investigate the localization transition in the integer quantum Hall regime and to measure the critical exponent v of the localization length ξ α |B - Bc|-v. Our results show a universal behaviour in the three lowest Landau levels. This is in agreement w universality statement of the field-theoretic approach to the metal-insulator transition in the quantum Hall effect. By studying the characteristic temperature Tc for different widths, the temperature exponent p 2 of the inelastic scattering length can also be measured.
AB - We have studied the magnetoresistance of AlGaAs/GaAs-heterojunctions at millikelvin temperatures in small Hall bar and Corbino geometries with different sizes. Below a characteristic temperature Tc which increases with decreasing sample width, the phase-breaking length Lin is larger than the sample size. Under these conditions the half width ΔB of the longitudinal magnetoresistance no longer depends upon temperature but only upon size. By varying the size it is thus possible to directly investigate the localization transition in the integer quantum Hall regime and to measure the critical exponent v of the localization length ξ α |B - Bc|-v. Our results show a universal behaviour in the three lowest Landau levels. This is in agreement w universality statement of the field-theoretic approach to the metal-insulator transition in the quantum Hall effect. By studying the characteristic temperature Tc for different widths, the temperature exponent p 2 of the inelastic scattering length can also be measured.
UR - http://www.scopus.com/inward/record.url?scp=0026819749&partnerID=8YFLogxK
U2 - 10.1016/0039-6028(92)90316-X
DO - 10.1016/0039-6028(92)90316-X
M3 - Article
AN - SCOPUS:0026819749
VL - 263
SP - 108
EP - 111
JO - Surface science
JF - Surface science
SN - 0039-6028
IS - 1-3
ER -