Measurement of Tunneling Conductance of Two-Dimensional Electrons in a Si MOSFET Nanostructure

The properties of strongly correlated two-dimensional electrons in semiconductor heterostructure continue to be of a fundamental interest of condensed matter physics [1]. A collection of transport studies have revealed a wealthy of interesting effects in the low-electron density limit, particularly in Si MOSFET structures [2]. In this talk, we present an alternative, tunneling conductance measurement of the 2D electrons in a Si MOSFET nanostructure. In our device, a global gate is used to control the 2D electron density. In addition, a set of small gates, as small as 50nm, forms a lateral tunneling barrier for the measurements. We find that there is a strong correlation between the still puzzling metal-insulator transition observed in transport [2] and our tunneling characteristics. The tunneling conductance is studied under different carrier density and in-plane Magnetic field. The project is supported by the NSF under Grant No. DMR-0804794. \\[4pt] [1] B. Spivak, S. V. Kravchenko, S. Kivelson, and X.P.A. Gao, Rev. Mod. Phys. 82, 1743 (2010). \newline [2] E. Abrahams, S. V. Kravchenko, M. P. Sarachik, Rev. Mod. Phys. 73, 251 (2001)