Electrostatic modification of the conductive properties of amorphous Bi ultrathin films

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.