Alexandre R Champagne

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We demonstrate a device geometry for single-molecule electronics experiments that combines both the ability to adjust the spacing between the electrodes mechanically and the ability to shift the energy levels in the molecule using a gate electrode. With the independent in-situ variations of molecular properties provided by these two experimental "knobs", we(More)
We study electron transport through C(60) molecules in the Kondo regime using a mechanically controllable break junction. By varying the electrode spacing, we are able to change both the width and the height of the Kondo resonance, indicating modification of the Kondo temperature and the relative strength of coupling to the two electrodes. The linear(More)
The ability to make electrical contact to single molecules creates opportunities to examine fundamental processes governing electron flow on the smallest possible length scales. We report experiments in which we controllably stretched individual cobalt complexes having spin S = 1, while simultaneously measuring current flow through the molecule. The(More)
We study 23-30 nm long suspended single-wall carbon nanotube quantum dots and observe both their stretching and bending vibrational modes. We use low-temperature DC electron transport to excite and measure the tubes' bending mode by making use of a positive feedback mechanism between their vibrations and the tunneling electrons. In these(More)
The possibility to make 10 nm scale, and low-disorder, suspended graphene devices would open up many possibilities to study and make use of strongly coupled quantum electronics, quantum mechanics, and optics. We present a versatile method, based on the electromigration of gold-on-graphene bow-tie bridges, to fabricate low-disorder suspended graphene(More)
We use interlayer tunneling to study bilayer two-dimensional electron systems at ␯ T = 1 over a wide range of charge-density imbalance ⌬␯ = ␯ 1 − ␯ 2 between the two layers. We find that the strongly enhanced tunneling associated with the coherent excitonic ␯ T = 1 phase at small layer separation can survive at least up to an imbalance of ⌬␯ = 0.5, i.e., ͑␯(More)
Making use of bipolar transport in single-wall carbon nanotube quantum transistors would permit a single device to operate as both a quantum dot and a ballistic conductor or as two quantum dots with different charging energies. Here we report ultra-clean 10 to 100 nm scale suspended nanotube transistors with a large electron-hole transport asymmetry. The(More)
We extract experimentally the electronic thermal conductivity, Ke, in suspended graphene that we dope using a back-gate electrode. We make use of two-point dc electron transport at low bias voltages and intermediate temperatures (50-160 K), where the electron and lattice temperatures are decoupled. The thermal conductivity is proportional to the charge(More)
The underlying nature of all materials is quantum. This means that their electrons and atoms are able to interfere (correlate) which each other, like waves, to display a very rich range of properties (e.g. superconductivity). Disorder destroys the delicate quantum correlations in materials, and leads to classical behavior. We set out to create systems with(More)
We study the Josephson-like interlayer tunneling signature of the strongly correlated nuT=1 quantum Hall phase in bilayer two-dimensional electron systems as a function of the layer separation, temperature, and interlayer charge imbalance. Our results offer strong evidence that a finite temperature phase transition separates the interlayer coherent phase(More)