Fano Effects in Transmissions through Fullerene C60 under Molecular Distortion

概要

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To investigate Fano resonances in the system of quantum dots (QDs), the conduction spectra for a fullerene C60 is calculated in consideration of distortion effects for some characteristic modes. In mesoscopic systems, the Fano effect has mainly been observed in an Aharonov–Bohm (AB) ring system with a QD. In the present paper, we would like to stress that a referential path of an AB ring is not required to obtain asymmetric Fano resonances in C60. The interference between a narrow peak and a long tail of a wide peak causes the Fano resonance in this molecule. The former plays the role of the discrete level and the latter the continuum state. These levels originate from a degenerate state through the effect of distortion. In particular, a dip structure giving zero conductance as the destructive interference appears in the cases of distortions with odd parity. In addition, another type of conductance dip is found at a multiply degenerate level when the electrodes are attached to C60 without axial symmetry. This type of conductance dip, which is induced from the 4th-order self-energy term, is reported for the first time in this paper. The dependence of this dip on temperature is also discussed.
2008-02-15