Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 73: Transport: Carbon Nanotubes (organized by TT)

TT 73.2: Talk

Wednesday, April 2, 2014, 16:45–17:00, HSZ 304

Valley-mixed states and energy splitting as a finite size effect in chiral carbon nanotubes — •Magdalena Marganska, Piotr Chudzinski, and Milena Grifoni — Institute for Theoretical Physics, University of Regensburg, Regensburg, Germany

The two main degrees of freedom of an electron in a carbon nanotube (CNT) are valley and spin. The electronic spectra obtained in transport experiments on CNT quantum dots in parallel magnetic field often show an anticrossing of spectral lines assigned to the opposite valleys. One source of this phenomenon could be the disorder, with impurity induced scattering. However, we show that this effect can be reproduced also in ultraclean CNTs, where it is caused solely by the presence of the boundaries. It is therefore a finite size effect, not an inherent property of the CNT. We identify the nanotube chirality class which supports this phenomenon and analyze its dependence on the CNT parameters and on the distance from the charge neutrality point.