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Janos Koltai

Publications and source records attributed to Janos Koltai.

2 recordsLinked to original sources

The Growth of New Extended Carbon Nanophases from Ferrocene Inside Single-Walled Carbon Nanotubes

The Raman response of new structures grown after filling SWCNTs with ferrocene and transformation at moderate high temperatures is demonstrated to be very strong, even stronger than the response from the tubes. Transmission electron microscopy demonstrates that the new objects are flat and exhibit a structure similar to short fragments of nanoribbons. The growth process is controlled by two different activation energies for low and high transformation temperatures, respectively. Immediately after filling Raman pattern from a precursor molecule are detected. Two different types of nanoribbons were identified by selecting special laser energies for the Raman excitation. These ribbons have the signature of quaterrylene and terrylene, respectively.

cond-mat.mtrl-sci

Nonthermal broadening in the conductance of double quantum dot structures

We study the transport properties of a double quantum dot (DQD) molecule at zero and at finite temperature. The properties of the zero temperature conductance depends on whether the level attraction between the symmetric and antisymmetric states of the DQD, produced by the coupling to the leads, exceeds or not the interdot tunneling. For finite temperature we find a remarkable nonthermal broadening effect of the conductance resonance, when the energy levels of the individual dots are detuned.

cond-mat.mes-hall