Abstract
An exact solution is presented for tunneling through a negative-U degenerate molecular quantum dot weakly coupled to electrical leads. The tunnel current exhibits hysteresis if the level degeneracy of the negative-U dot is larger than 2. Switching occurs in the voltage range as a result of attractive electron correlations in the molecule, which open up a new conducting channel when the voltage is above the threshold bias voltage Once this current has been established, the extra channel remains open as the voltage is reduced down to the lower threshold voltage The current hysteresis vanishes above some critical temperature. Possible realizations of bistable molecular quantum dots are fullerenes, especially and mixed-valence compounds.
- Received 13 August 2002
DOI:https://doi.org/10.1103/PhysRevB.67.075301
©2003 American Physical Society