Switching and Memory Effects in Molecular Junctions

Pino D'Amico

Tuesday, 20 March 2012, 12:30
Matfys library

In the field of molecular electronics, effects like charge-memory, bistability and switching between charged and neutral states have been observed in STM [1] and molecular junctions [2,3] experiments. In this work we use model hamiltonians to describe molecular junctions, taking into account the interaction between the electronic levels and the vibrational degrees of freedom (vibrons) of the molecule. For a molecular level coupled to a vibron and in the presence of leads, we show that upon applying gate or bias voltage, it is possible to induce charge-bistability and hysteresis [4,5]. We further propose theoretically a spin-memory effect in quantum dots and single molecules coupled to ferromagnetic leads showing that the switching between spin states can be achieved by electrical control [6]. Finally we propose possible extensions to chains and lattices of molecular junctions in collaboration with E. Mentovich and coworkers from Tel Aviv University.

[1] J. Repp, G. Meyer, F. E. Olsson, M. Persson, Science 305, 493 (04).
[2] E. Loertscher, J.W. Ciszek, J. Tour, H. Riel, Small 2, 973 (06).
[3] E. Mentovich, B. Belgorodsky, I. Kalifa, S. Richter, Advanced Materials 22 , 2182, (10).
[4] D. A. Ryndyk, P. D'Amico, G. Cuniberti, K. Richter, PRB 78, 085409 (08).
[5] P. D'Amico, D. A. Ryndyk, G. Cuniberti, K. Richter, NJP 10, 085002 (08).
[6] D. A. Ryndyk, P. D'Amico, K. Richter, PRB 81, 115333 (10).