Robust Secondary Electron Interference in Suspended Carbon Nanotubes

Quantum interference of electron waves in devices with the size close to the electron coherence length has been studied in various fields such as Aharonov-Bohm and quantum Hall effect. Fabry-Perot (FP) oscillations arise from electron interferences in carbon nanotubes and can be seen as conductance oscillations as a function of gate voltage [1]. Electron interferences can cause another oscillation in addition to FP in carbon nanotubes [2]. Dirnaichner et al observed these oscillations and suggested that they come from the symmetry of the carbon nanotubes [3]. These oscillations have been referred to as slow oscillations due to their larger period compare to the FP oscillations.
In this work we study both FP and slow oscillations in clean suspended carbon nanotubes. We investigate the origin of slow oscillations using our experimental data and theoretical calculations. We show that slow oscillations are more robust compare to FP and can survive up to 70 K.

References

[1] W. Liang, M. Bockrath, D. Bozovic, J.H. Hafner, M. Tinkham and H. Park, Nature 411, 665 (2001)
[2] J. Jiang, J. Dong and D.Y. Xing, Phys. Rev. Lett. 91, 056802 (2003).
[3] A. Dirnaichner, M. del Valle, K.J.G. Gotz, F.J. Schupp, N. Paradiso, M. Grifoni, Ch. Strunk and A.K. Huttel, Phys. Rev. Lett. 117, 166804 (2016).