Entanglement in a three spin system controlled by electric and magnetic fields

• Published in: Journal of physics. Condensed matter Vol. 24; no. 37; p. 375303
• Main Authors: uczak, Jakub, Bu ka, Bogdan R
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 19.09.2012; Institute of Physics
• Subjects: Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Correlation; Coupling (molecular); Electric fields; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Entanglement; Exact sciences and technology; Magnetic fields; Magnetic flux; Physics; Quantum dots; Stark effect; Magnetic flux; Quantum entanglement; Quantum dots; Chirality; Electric field effects; Superexchange interactions; Magnetic field effects; Stark effect; Spin correlation function
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/24/37/375303

We study the effect of electric field and magnetic flux on spin entanglement in an artificial triangular molecule built of coherently coupled quantum dots. In a subspace of doublet states an explicit relation of concurrence with spin correlation functions and chirality is presented. The electric field modifies superexchange correlations and shifts many-electron levels (the Stark effect), as well as changing spin correlations. For some specific orientation of the electric field one can observe monogamy, for which one of the spins is separated from two others. Moreover, the Stark effect manifests itself in a different spin entanglement for small and strong electric fields. The role of magnetic flux is opposite: it leads to circulation of spin supercurrents and spin delocalization.