A quantum dot memory cell based on spin polaron formation

A theoretical study that explores the feasibility of a new spin-based nonvolatile memory concept is presented. The active region of the memory cell is a semiconductor quantum dot (QD) sharing an interface with a dielectric ferromagnetic layer (FML). The operating principle of the device is based on the spontaneous magnetic symmetry breaking due to exchange interaction between the magnetic ions in the FML and the spins of the itinerant holes in the QD. As a result, the formation of bistable states is possible at some conditions. We find the parameters window that admits the bistability and consider its lifetime (bit retention time) as the QD is scaled down. The analysis is carried out for two different QD materials: a non-magnetic (NM) QD and a diluted magnetic semiconductor (DMS) QD. In addition, two different designs are considered: a QD sharing an interface with the FML and a QD embedded in the FML. The proposed device is ready for scalability, potentially down to a few hole level by reducing the size of the QD, and it promises high integration density since only two terminals are used for device operation.