Goker Ali, Goyer Francois, Ernzerhof Matthias
Departement de Chimie, Universite de Montreal, C.P. 6128, Succursale A, Montreal, Quebec H3C 3J7, Canada.
J Chem Phys. 2008 Nov 21;129(19):194901. doi: 10.1063/1.3013815.
We present a simple model for a fundamental process in molecular electronics: The change in conductance upon bond breaking. In our model, a diatomic molecule is attached to spin-polarized contacts. Employing a Hubbard Hamiltonian, electron interaction is explicitly considered in the molecule and neglected in the contacts, enabling us to study the impact of electron interaction on the molecular conductance. In the limit where the electron repulsion is strong compared to the binding energy (as is the case upon dissociation), electron transmission is strongly suppressed compared to the noninteracting case. On the other hand, the spin-polarized contacts introduce a coupling between the molecular singlet and triplet states, as a consequence of which the energy gap between the lowest resonances is reduced.
键断裂时的电导变化。在我们的模型中，一个双原子分子连接到自旋极化的触点上。采用哈伯德哈密顿量，明确考虑了分子中的电子相互作用，而在触点中忽略了这种相互作用，这使我们能够研究电子相互作用对分子电导的影响。在电子排斥力比结合能强的极限情况下（如解离时的情况），与非相互作用情况相比，电子传输受到强烈抑制。另一方面，自旋极化的触点在分子单重态和三重态之间引入了耦合，其结果是最低共振之间的能隙减小。
