Fig. 2. Experimental setup and transport signature.

a Scanning electron microscope image of the device: At the edge of an etched cantilever, a nanotube is positioned on two contacts (S,D) and suspended over a piano of seven gates. The conductance through the device is measured with an AC excitation on S (V_ex at ~1.5 MHz) and a cryogenic LC tank circuit connected to the drain (D) followed by a cold HEMT amplifier. b Measured conductance, G, as a function of gate voltage common to all seven gates, V_G, and B_||, exhibiting a zig-zag of bright and dark charging lines (the latter marked by dashed blue). c Zoom-in on one triple point, with the schematic lines separating the $∣N⟩$, $∣D⟩$ and $∣B⟩$ states are marked as in Fig. 1c.