Thermodynamic Signature of a Two-Dimensional Metal-Insulator Transition

Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095, USA.
Physical Review Letters (Impact Factor: 7.51). 06/2000; 84(20):4689-92. DOI: 10.1103/PhysRevLett.84.4689
Source: PubMed


We present a study of the compressibility kappa of a two-dimensional hole system which exhibits a metal-insulator phase transition at zero magnetic field. It has been observed that dkappa/dp changes sign at the critical density for the metal-insulator transition. Measurements also indicate that the insulating phase is incompressible for all values of B. Finally, we show how the phase transition evolves as the magnetic field is varied and construct a phase diagram in the density-magnetic field plane for this system.

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Available from: Shane Dultz, Jun 20, 2014
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    • "Hence, the " metal-insulator " transition around p cr itical may be attributed to this negative compressibility , which is also observed for a 2DHS [23], [24]. The critical transition density for a 2DHS inside GaAs [24] is p cr itical = 5.5 × 10 10 cm −2 . The charge control model [22] applied to the dark C-V of the MSM-2DHS, however, yields p 2D H S | "
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    • "The negative current observed at low carrier densities reveals that the electric field penetrating through the metallic interface is negative, which arises from overscreening of the external field by the mobile electrons at the LAO/STO interface. To further explore the electronic properties of the interface, we follow the analysis of Ref. [9] "
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