Measurements of the density-dependent many-body electron mass in two dimensional GaAs/AlGaAs heterostructures.
We determine the density-dependent electron mass m(*) in two-dimensional electron systems of GaAs/AlGaAs heterostructures by performing detailed low-temperature Shubnikov-de Haas measurements. Using very high-quality transistors with tunable electron densities we measure m(*) in single, high mobility specimens over a wide range of r(s) (6 to 0.8). Toward low densities we observe a rapid increase of m(*) by as much as 40%. For 2>r(s)>0.8 the mass values fall approximately 10% below the band mass of GaAs. Numerical calculations are in qualitative agreement with our data but differ considerably in detail.
Tan
Y-W
YW
Department of Physics, Columbia University, New York, New York 10027, USA.
Zhu
J
J
Stormer
H L
HL
Pfeiffer
L N
LN
Baldwin
K W
KW
West
K W
KW