@article{enaya_semenov_zavada_kim_2008, title={Magnetic polaron for a spin memory application}, volume={104}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.3000482}, DOI={10.1063/1.3000482}, abstractNote={A memory concept based on the interfacial exchange energy between itinerant holes in a quantum dot and magnetic ions in an adjacent magnetic insulator is theoretically investigated. A model based on the free energy analysis demonstrates the existence of bistable states through the mechanism of bound collective magnetic polaron, whose formation and dissolution can be controlled electrically via a gate bias pulse. The parameter window suitable for bistability is discussed along with the conditions that support maximum nonvolatility. The analysis is extended to the influence of material choices as well as different designs. The calculation results clearly indicate the possibility of room temperature operation, given the availability of insulating ferromagnetic or antiferromagnetic materials whose Curie temperature is above room temperature.}, number={8}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Enaya, H. and Semenov, Y. G. and Zavada, J. M. and Kim, K. W.}, year={2008}, month={Oct}, pages={084306} }
 @article{enaya_semenov_kim_zavada_2008, title={Nonvolatile Memory via Spin Polaron Formation}, volume={7}, ISSN={1536-125X 1941-0085}, url={http://dx.doi.org/10.1109/TNANO.2008.926332}, DOI={10.1109/TNANO.2008.926332}, abstractNote={A nonvolatile memory is explored theoretically by utilizing the magnetic exchange interaction between localized holes and an adjacent ferromagnetic (FM) material. The active device consists of a buried semiconductor quantum dot (QD) and an FM insulating layer that share an interface. The hole population in the QD is controlled by particle transfer with a reservoir of itinerant holes over a permeable barrier. A theoretical model based on the free energy calculation demonstrates the existence of a bistable state through the mechanism of a collective spin polaron, whose formation and dissolution can be manipulated electrically via a gate bias pulse. The parameter space window suitable for bistability is examined along with the conditions that support maximum nonvolatility. The limitation of QD size scaling is analyzed in terms of the bit retention time.}, number={4}, journal={IEEE Transactions on Nanotechnology}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Enaya, H. and Semenov, Y.G. and Kim, K.W. and Zavada, J.M.}, year={2008}, month={Jul}, pages={480–483} }
 @article{enaya_semenov_kim_zavada_2007, title={Electrical Manipulation of Nonvolatile Spin Cell Based on Diluted Magnetic Semiconductor Quantum Dots}, volume={54}, ISSN={0018-9383}, url={http://dx.doi.org/10.1109/TED.2007.894377}, DOI={10.1109/TED.2007.894377}, abstractNote={In this paper, electrical manipulation of a memory cell based on a semiconductor nanostructure consisting of a diluted magnetic semiconductor (DMS) quantum dot (QD) and a reservoir of itinerant holes separated by an energy barrier is investigated theoretically. The operating principle takes advantage of the paramagnetic-ferromagnetic (PM-FM) phase transition mediated by the itinerant holes in the DMS QD that can lead to electrically controlled write/erase operations. Nonvolatility can be achieved when the structure is properly designed to reach a thermodynamic equilibrium at both the PM and FM configurations (i.e., bistability). Assuming a parabolic confining potential in the QD, the performance characteristics of the proposed nanostructure are analyzed including the scalability and the lifetime. An advantage of this memory concept is the extremely small dissipative energy for write/erase functions due to the open-circuit nature of the process. A readout scheme enabling electrical detection, with the repetition rate up to the 10-100-MHz range, is also explored by utilizing only two contacts. Finally, a potential application of the proposed memory cell is discussed as a rudimentary device for logic AND and OR operations}, number={5}, journal={IEEE Transactions on Electron Devices}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Enaya, Hani and Semenov, Yuriy G. and Kim, K. W. and Zavada, John M.}, year={2007}, month={May}, pages={1032–1039} }
 @article{semenov_enaya_kim_2005, title={Bistability in a magnetic and nonmagnetic double-quantum-well structure mediated by the magnetic phase transition}, volume={86}, ISSN={0003-6951}, url={http://dx.doi.org/10.1063/1.1864237}, DOI={10.1063/1.1864237}, abstractNote={The hole distribution in a double-quantum-well (QW) structure consisting of a magnetic and a nonmagnetic semiconductor QW is investigated as a function of temperature, the energy shift between the QWs, and other relevant parameters. When the itinerant holes mediate the ferromagnetic ordering, it is shown that a bistable state can be formed through hole redistribution, resulting in a significant change in the properties of the constituting magnetic QW (i.e., the paramagnetic-ferromagnetic transition). The model calculation also indicates a large window in the system parameter space where bistability is possible. Hence, this structure could form the basis of a stable memory element that may be scaled down to a few-hole regime.}, number={7}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Semenov, Y. G. and Enaya, H. and Kim, K. W.}, year={2005}, pages={073107} }