Blocking-state influence on shot noise and conductance in quantum dots

Abstract

Quantum dots (QDs) investigated through electron transport measurements often exhibit varying, state-dependent tunnel couplings to the leads. Under specific conditions, weakly coupled states can result in a strong suppression of the electrical current and they are correspondingly called blocking states. Using the combination of conductance and shot noise measurements, we investigate blocking states in carbon nanotube (CNT) QDs. We report negative differential conductance and super-Poissonian noise. The enhanced noise is the signature of electron bunching, which originates from random switches between the strongly and weakly conducting states of the QD. Negative differential conductance appears here when the blocking state is an excited state. In this case, at the threshold voltage where the blocking state becomes populated, the current is reduced. Using a master equation approach, we provide numerical simulations reproducing both the conductance and the shot noise pattern observed in our measurements.

10 pages, 7 figures

References in corpus (11)

• Full counting statistics of super-Poissonian shot noise in multi-level quantum dots
• Counting statistics and super-Poissonian noise in a quantum dot
• Super-poissonian noise, negative differential conductance, and relaxation effects in transport through molecules, quantum dots and nanotubes
• Universality of Non-equilibrium Fluctuations in Strongly Correlated Quantum Liquids
• Bimodal Counting Statistics in Single Electron Tunneling through a Quantum Dot
• Full counting statistics and shot noise of cotunneling in quantum dots and single-molecule transistors
• Shot noise spectroscopy on a semiconductor quantum dot in the elastic and inelastic cotunneling regimes
• Electron Bunching in Transport Through Quantum Dots in High Magnetic Field
• Stamping single wall nanotubes for circuit quantum electrodynamics
• Realization of GHz-frequency impedance matching circuits for nano-scale devices
• Measurements of a Quantum Dot with an Impedance-Matching On-Chip LC Resonator at GHz Frequencies

Cited by in corpus (5)

• Shot Noise in Mesoscopic Systems: from Single Particles to Quantum Liquids
• Dark states in a carbon nanotube quantum dot
• Noise insights into electronic transport
• Strongly correlated charge transport in silicon MOSFET quantum dots
• Dark versus blocking states in electronic transport: a Lee-Yang zero analysis of full counting statistics