We theoretically examine the effects of polaron formation in quantum dots onthe transport properties. When a separation between two electron-levels in aquantum dot matches the energy of the longitudinal optical (LO) phonons, thepolarons are strongly formed. The Rabi splitting between the levels isobservable in a peak structure of the differential conductance G as a functionof the bias voltage. The polaron formation suppresses the peak height of G,which is due to the competition between the resonant tunneling (resonancebetween a level in the dot and states in the leads) and the polaron formation(Rabi oscillation between two levels in the dot). G shows a sharp dip at themidpoint between the split peaks. This is attributable to the destructiveinterference between bonding and anti-bonding states in a composite system ofelectrons and phonons.
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