Compressibility of the Interacting Two-Dimensional Electron Gas
A new technique has been employed to study the compressibility of the two-dimensional electron gas. This technique, based upon a double-layer 2D system, is typically 100 times more sensitive than the traditional capacitance method. Using high mobility 2D systems we have observed regimes of negative thermodynamic compressibility both at zero magnetic field and in the extreme quantum limit. These regimes signal the dominance of electron-electron interactions over kinetic effects. Negative compressibility anomalies are also found near the fractional Hall states at ν = 1/3 and 2/3. These latter features represent thermodynamic signatures of the interacting quasiparticle gases which exist along with the condensed ground state.
KeywordsGate Bias Penetration Field Fractional Quantum Hall Effect Gate Field Gate Bias Versus
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