Switchable Coupling of Vibrations to Two-Electron Carbon-Nanotube Quantum Dot States.

Weber, P; Calvo, H L; Bohle, J; Goß, K; Meyer, C; Wegewijs, M R; Stampfer, C · Nano Lett · 2015

basic_science · Level V

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Abstract

We report transport measurements on a quantum dot in a partly suspended carbon nanotube. Electrostatic tuning allows us to modify and even switch "on" and "off" the coupling to the quantized stretching vibration across several charge states. The magnetic-field dependence indicates that only the two-electron spin-triplet excited state couples to the mechanical motion, indicating mechanical coupling to both the valley degree of freedom and the exchange interaction, in contrast to standard models.