title: Measurements of the density-dependent many-body electron mass in two dimensional GaAs/AlGaAs heterostructures.
abstract: 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.
authors.affiliation: Department of Physics, Columbia University, New York, New York 10027, USA.
authors.forename: Y-W
authors.initials: YW
authors.lastname: Tan
authors.forename: J
authors.initials: J
authors.lastname: Zhu
authors.forename: H L
authors.initials: HL
authors.lastname: Stormer
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: K W
authors.initials: KW
authors.lastname: Baldwin
authors.forename: K W
authors.initials: KW
authors.lastname: West