quantum-logic operations for nanospintronic devices
报 告 人： Dr. habil.
to the rapid development of conventional computer devices, the applied
semiconductor-based technologies are slowly reaching their physical limits with
respect to both size and speed. Therefore, for future nanoscale functional
devices it becomes more and more important to investigate alternative ideas.
One promising road is to use the spin degree of freedom (spintronics) and to
combine it with optical control (nano-spintronics).
In this talk I will first introduce some fundamental
ideas needed for the logic functionalization of magnetic systems based on ab
initio quantum many-body theory. The unitary time evolution of both extended
and molecular systems allows for the description of coherent dynamics on the
subpicosecond time scale. The first-principles separation of laser-induced spin
and charge dynamics benefits from the strong electronic correlations in
magnetic materials . The Λ process represents a mechanism which allows for
the rapid optical manipulation of the magnetic state of realistic molecules
[2,3] bypassing slow dynamical degrees of freedom.
Based on these concepts I will then present several
results, which show that the molecular spins can encode information in a
variety of laser-driven, logical processes, going far beyond simple information
storage. As main examples of functionalities on magnetic molecules I will
address the implementation of Boolean logic (AND, OR, and XOR gates), the
spin-SHIFT register, as well as the ERASE operation. Finally, I will address
some new concepts such as mechanically controlled spin dynamics , the
inclusion of the molecular rotation , as well as the which-path
interference, in which the final state of the spin reveals the path followed
during the spin-transfer process .
Zhang, W. Hübner, G. Lefkidis, Y. Bai, and T. F. George, Nature Physics 5, 499 (2009).
Jin, F. Rupp, K. Chevalier, M. M. N. Wolf, M. Colindres Rojas, G. Lefkidis,
H.-J. Krüger, R. Diller, and W. Hübner,
Phys. Rev. Lett. 109, 267209 (2012).
Chaudhuri, W. Jin, G. Lefkidis, and W. Hübner, J. Chem. Phys. 143, 174303 (2015).
Li, J. Liu, S. Zhang, G. Lefkidis, and W. Hübner, Carbon 87, 153 (2015).
Jin, D. Chaudhuri, C. Li, G. Lefkidis, and W. Hübner, J. Supercond. Nov. Magn 30, 801 (2017).
Chaudhuri, G. Lefkidis, and W. Hübner, Phys. Rev. B 96,
Dr. habl. Georgios
Lefkidis received his M.S degree and doctoral degree in Aristotle University
Thessaloniki in 1995 and 2002, respectively. From 2003, he worked in Kaiserslautern
University of Technology as a Post-doctoral researcher for four years.
Currently he is a tenured lecturer with a Habilitation title in TU Kaiserslautern.
His main research fields are electronic ab-initio theory of magneto-optics, laser-induced spin and charge dynamics, quantum
thermodynamics, and logic functionalization of magnetic nanostructures for
logic units and spintronics devices. Till now he has contributed 57 peer
reviewed publications (PRL, Nature Physics, PRB et al.), 1 book chapter, and 35 invited talks. Also, he is a
referee for several journals (e.g., American Physical Society and Physica