Resonant Tunneling in a Dissipative Environment

TL;DR

This paper investigates how dissipation from resistive leads affects electron tunneling in a carbon nanotube quantum dot, revealing non-monotonic temperature dependence of conductance peaks due to a transition from sequential to resonant tunneling.

Contribution

It demonstrates the impact of a dissipative environment on tunneling regimes and characterizes the non-monotonic temperature dependence of conductance peaks in a quantum dot system.

Findings

Conductance peak height increases with decreasing temperature in sequential tunneling.

Peak width saturates at low temperatures in the resonant tunneling regime.

Peak height decreases at low temperatures, showing non-monotonic behavior.

Abstract

We measure tunneling through a single quantum level in a carbon nanotube quantum dot connected to resistive metal leads. For the electrons tunneling to/from the nanotube, the leads serve as a dissipative environment, which suppresses the tunneling rate. In the regime of sequential tunneling, the height of the single-electron conductance peaks increases as the temperature is lowered, although it scales more weekly than the conventional 1/T. In the resonant tunneling regime (temperature smaller than the level width), the peak width approaches saturation, while the peak height starts to decrease. Overall, the peak height shows a non-monotonic temperature dependence. We associate this unusual behavior with the transition from the sequential to the resonant tunneling through a single quantum level in a dissipative environment.