The application of the field-effect transistor principle to novel materials to achieve electrostatic doping is a relatively new research area with roots that go back to the turn of the 20th century. The technique in principle provides the opportunity to modify the electronic and magnetic properties of materials through controlled and reversible changes in carrier concentration, without altering the degree of disorder or the chemical composition. Electrostatic doping can also serve as a tool for studying quantum critical behavior, by allowing the ground state of a system to be tuned in a controlled fashion. This is precisely what has been done in tuning the transition between insulating and superconducting ground states of ultrathin films of amorphous bismuth.
Bibliographical noteFunding Information:
The authors would like to thank Guy Deutscher for pointing out the issue associated with the logarithmic dependence of the conductance on temperature in superconducting films. They would also like to thank Boris Shklovskii, Leonid Glazman, and Alex Kamenev for useful discussions. This work was supported in part by the National Science Foundation under Grant NSF/DMR- 0455121.
- Electrostatic charging
- Quantum criticality
- Superconductor-insulator transitions