An alternative approach to tunable spin-FET with nonmagnetic high-mobility heterostructures

Summary form only given. Ultra high-mobility GaAs/AlGaAs heterostructures are excellent systems for simulating elementary magnetic interactions with great control. The usual methods of generating magnetism in these semiconducting systems are two-fold: (1) defining quantum dot assemblies where each dot contains an odd number of electrons so that they play the role of ^/-electrons embedded in a metallic matrix, or (2) doping GaAs with magnetic atoms such as Mn. Here we propose a new route towards achieving a long-range magnetism in GaAs/AlGaAs heterostructures that does not require either formation of quantum dots or external doping of magnetic atoms. The idea is based on a two-component nature of background potential fluctuations in modulation-doped GaAs/AlGaAs systems which naturally trap localized spins at specific values of conduction electron density. The spins are placed roughly uniformly at ~ few hundred nanometers within the 2D electron gas, and manifest in unexpectedly complex behavior of transport and thermodynamic properties of the 2D system at mesoscopic length scales. A surface gate can modulate the mutual interaction between the spins, making the magnetic state tunable electrically. Although the present devices required the experiments to be carried out at sub-Kelvin temperature range, we suggest that such a model can be utilized in incorporating magnetism in low-dimensional semiconductors over a wide parameter range.