Critical behaviour of the Pauli spin susceptibility of strongly correlated electrons in two dimensions

Abstract

Thermodynamic measurements reveal that the Pauli spin susceptibility in a strongly correlated low-disorder two-dimensional electron system in silicon becomes enhanced by almost an order of magnitude at low electron densities and has a critical behaviour close to the metal--insulator transition point. This provides thermodynamic evidence for the existence of a phase transition. The nature of the low-density phase still remains unclear because it is masked by the residual disorder in the electron system.

Acknowledgements

We gratefully acknowledge discussions with S. Chakravarty, D. Heiman, N.E. Israeloff, R.S. Markiewicz, M.P. Sarachik and A. Widom. One of us (SVK) would like to thank B.I. Halperin for suggesting this method to measure spin susceptibility. We would also like to thank A. Gaidarzhy and J.B. Miller for technical assistance and C.M. Marcus and P. Mohanty for an opportunity to use their microfabrication facilities. This work was supported by National Science Foundation grant DMR-0403026, the Russian Foundation for Basic Research, the Russian Academy of Science, and the Programme ‘The state support of leading scientific schools’.

Notes

^† The value n _c was determined from transport measurements 5, 6.