arXiv subjects

Jan A. Mol

Publications and source records attributed to Jan A. Mol.

23 records · Page 2Linked to original sources

arXiv2017

A double quantum dot memristor

Memristive systems are generalisations of memristors, which are resistors with memory. In this paper, we present a quantum description of memristive systems. Using this model we propose and experimentally demonstrate a simple and practical scheme for realising memristive systems with quantum dots. The approach harnesses a phenomenon that is commonly seen as a bane of nanoelectronics, i.e. switching of a trapped charge in the vicinity of the device. We show that quantum-dot memristive systems have hysteresis current-voltage characteristics and quantum jump induced stochastic behaviour. Realising such a quantum memristor completes the menu of components for quantum circuit design.

cond-mat.mes-hall↗

arXiv2017

Scaling limits of graphene nanoelectrodes

Graphene is an ideal material for fabricating atomically thin nanometre spaced electrodes. Recently, carbon-based nanoelectrodes have been employed to create single-molecule transistors and phase change memory devices. In spite of the significant recent interest in their use in a range of nanoscale devices from phase change memories to molecular electronics, the operating and scaling limits of these electrodes are completely unknown. In this paper, we report on our observations of consistent voltage driven resistance switching in sub-5 nm graphene nanogaps. We find that we are able to reversibly cycle between a low and a high resistance state using feedback-controlled voltage ramps.We attribute this unexplained switching in the gap to the formation and breakdown of carbon filaments.By increasing the gap, we find that such intrinsic resistance switching of graphene nanogaps imposes a scaling limit of 10 nm (approx.) on the gap-size for devices with operating voltages of 1 to 2 volts.

cond-mat.mes-hall↗

arXiv2017

Vibrational effects in charge transport through a molecular double quantum dot

Recent progress in the field of molecular electronics has revealed the fundamental importance of the coupling between the electronic degrees of freedom and specific vibrational modes. Considering the examples of a molecular dimer and a carbon nanotube double quantum dot, we here theoretically investigate transport through a two-site system that is strongly coupled to a single vibrational mode. Using a quantum master equation approach, we demonstrate that, depending on the relative positions of the two dots, electron-phonon interactions can lead to negative differential conductance and suppression of the current through the system. We also discuss the experimental relevance of the presented results and possible implementations of the studied system.

cond-mat.mes-hall↗

arXiv2016

Quantum Interference in Graphene Nanoconstrictions

We report quantum interference effects in the electrical conductance of chemical vapor deposited graphene nanoconstrictions fabricated using feedback controlled electroburning. The observed multimode Fabry-Perot interferences can be attributed to reflections at potential steps inside the channel. Sharp antiresonance features with a Fano line shape are observed. Theoretical modeling reveals that these Fano resonances are due to localized states inside the constriction, which couple to the delocalized states that also give rise to the Fabry-Perot interference patterns. This study provides new insight into the interplay between two fundamental forms of quantum interference in graphene nanoconstrictions.

cond-mat.mes-hall↗

arXiv2015

Three-terminal graphene single-electron transistor fabricated using feedback-controlled electroburning

We report room-temperature Coulomb blockade in a single layer graphene three-terminal single-electron transistor (SET) fabricated using feedback-controlled electroburning. The small separation between the side gate electrode and the graphene quantum dot results in a gate coupling up to 3 times larger compared to the value found for the back gate electrode. This allows for an effective tuning between the conductive and Coulomb blocked state using a small side gate voltage of about 1V. The technique can potentially be used in the future to fabricate all-graphene based room temperature single-electron transistors or three terminal single molecule transistors with enhanced gate coupling.

cond-mat.mes-hall↗