Scaling of the magnetoconductivity of silicon MOSFETs: evidence for a quantum phase transition in two dimensions.
For a broad range of electron densities n and temperatures T, the in-plane magnetoconductivity of the two-dimensional system of electrons in silicon MOSFETs can be scaled onto a universal curve with a single parameter H(sigma)(n,T), where H(sigma) obeys the empirical relation H(sigma) = A(n) [Delta(n)(2)+T2](1/2). The characteristic energy k(B)Delta associated with the magnetic field dependence of the conductivity decreases with decreasing density, and extrapolates to 0 at a critical density n(0), signaling the approach to a zero-temperature quantum phase transition. We show that H(sigma) = AT for densities near n(0).
Vitkalov
S A
SA
Physics Department, City College of the City University of New York, New York, New York 10031, USA.
Zheng
H
H
Mertes
K M
KM
Sarachik
M P
MP
Klapwijk
T M
TM