Dr Jan Mol

UKRI Future Leaders Fellow | Materials Research Institute Academic Fellow | Senior Lecturer
Email: j.mol@qmul.ac.ukTelephone: 020 7882 5582Room Number: G. O. Jones Building, Room 222Website: https://mollab.uk
Research
Research Interests:
In situ microscopy
Charge and heat transport in graphene nanostructures depend critically on their atomistic details. We combine cryogenic transport measurements with a wide range of in situ methods, including transmission electron microscopy and scanning thermal microscopy, to investigate the microscopic origins of effects such as Fabri-Pérot interference, Peltier heating/cooling and Franck-Condon blockade.
Transmission electron microscopy Graphene-based nanoscale quantum devices are an ideal platform for molecular electronics, advanced sensing, and understanding quantum phenomena. A key challenge to their realization is the understanding of the atomic and molecular configuration of the system and particularly how this influences the stability, sensitivity, and capability of the devices. To address this challenge, we have developed a high-yield process to fabricate suspended graphene nanodevices compatible with low-voltage aberration-corrected scanning transmission electron microscopy (AC-STEM) and to correlate atomic-scale characterization with quantum transport measurements obtained from the same devices.
Scanning thermal microscopy | |
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Nanostructuring can strongly alter the thermoelectric properties of materials. We use a scanning thermal microscope (SThM) to map the spatial dependence of nanoscale heating and cooling resulting from the electrical current flowing through an active device. By heating the SThM tip and measuring the voltage drop over the global contacts, we can also map the thermovoltage of the same device. Both the Seebeck and Peltier coefficients can be mapped with a lateral resolution of tens of nanometres. Recent publications:
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Quantum transport in nanoscale electronic devices
Electron transfer is perhaps the most ubiquitous molecular process, and has received a constant attention for nearly a century. Single-molecule transistors provide an exciting platform for studying electron transfer mechanism under conditions that are inaccessible in other experimental setups, and on a scale of individual molecules. We study charge transport through atomic- and molecular-scale transistors to uncover the quantum mechanical nature underlying charge and heat transport.
Quantum interference A key feature of electron transport through atomic- and molecular-scale nanostructures is the appearance of transport resonances associated with quantum interference. Examples include Breit–Wigner resonances, multipath Fabry–Pérot resonances, and Fano resonances. We study quantum interference in electroburnt graphene nanoconstrictions, top-down fabricated silicon nanowires, and single-molecule transistors.
Electron-phonon coupling Coupling between electronic and vibrational degrees of freedom in single-molecule devices can lead to transport properties very different from those of metal/semiconductor nanostructures. Charge transfer can excite vibrational modes, or phonons, and strong electron–phonon coupling leads to suppression of tunnel current at low bias voltages – so-called Franck-Condon blockade. Analogous to exciton transport in vivo (which has attracted a great deal of attention in the nascent field of quantum biology) vibrational interactions in molecular systems can also significantly enhance the efficiency of charge transport.
Heat-to-electricity conversion Conventional heat engines convert a temperature difference into mechanical work. Similarly, molecular heat engines use quantum transport to turn a thermal energy into electrical power. Nanoscale heat engines are small and do not have any moving parts, therefore they are ideal for low-power applications. We can measure the thermoelectric power conversion of a single molecule or graphene quantum dot device. The energy conversion rates achieved in these devices can be tuned close to the theoretical limit by carefully engineering the electronic energy levels, thus providing a viable pathway towards on-chip cooling and energy harvesting for quantum technologies.
Graphene-based molecular biosensing
Nanoscale biosensor technologies hold the promise of revolutionizing techniques ranging from biological interfaces to rapid pathogen detection to enabling DNA data storage. With high accuracy, sensitivity, and affordability, these sensors are predicted to drive a shift to personalized medicine and rapid diagnostics in real-time anywhere in the world. We are utilizing graphene as the active component for scalable tunneling sequencing methods.
Publications
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Sowa JK, Mol JA, Briggs GAD et al. (2020). Erratum: Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework (Journal of Chemical Physics (2018)(149) (154112) DOI: 10.1063/1.5049537). nameOfConference
DOI: 10.1063/5.0004514
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Fried JP, Bian X, Swett JL et al. (2020). Large amplitude charge noise and random telegraph fluctuations in room-temperature graphene single-electron transistors. nameOfConference
DOI: 10.1039/c9nr08574b
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Thomas JO, Limburg B, Sowa JK et al. (2019). Understanding resonant charge transport through weakly coupled single-molecule junctions. nameOfConference
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Limburg B, Thomas JO, Sowa JK et al. (2019). Charge-state assignment of nanoscale single-electron transistors from their current-voltage characteristics. nameOfConference
DOI: 10.1039/c9nr03754c
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Sowa JK, Mol JA, Gauger EM (2019). Marcus Theory of Thermoelectricity in Molecular Junctions. nameOfConference
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Schupp FJ, Mirza MM, MacLaren DA et al. (2018). Quantum interference in silicon one-dimensional junctionless nanowire field-effect transistors. nameOfConference
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Harzheim A, Spiece J, Evangeli C et al. (2018). Geometrically Enhanced Thermoelectric Effects in Graphene Nanoconstrictions. nameOfConference
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Sowa JK, Mol JA, Briggs GAD et al. (2018). Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework.. nameOfConference
DOI: 10.1063/1.5049537
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Puczkarski P, Wu Q, Sadeghi H et al. (2018). Low-Frequency Noise in Graphene Tunnel Junctions. nameOfConference
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Limburg B, Thomas JO, Holloway G et al. (2018). Anchor Groups for Graphene-Porphyrin Single-Molecule Transistors. nameOfConference
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Fried JP, Swett JL, Bian X et al. (2018). Challenges in fabricating graphene nanodevices for electronic DNA sequencing. nameOfConference
DOI: 10.1557/mrc.2018.187
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Sowa JK, Mol JA, Briggs GAD et al. (2018). Spiro-Conjugated Molecular Junctions: Between Jahn-Teller Distortion and Destructive Quantum Interference. nameOfConference
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Mirza MM, Schupp FJ, Mol JA et al. (2017). One dimensional transport in silicon nanowire junction-less field effect transistors. nameOfConference
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Gehring P, Harzheim A, Spièce J et al. (2017). Field-Effect Control of Graphene-Fullerene Thermoelectric Nanodevices. nameOfConference
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Sowa JK, Mol JA, Briggs GAD et al. (2017). Environment-assisted quantum transport through single-molecule junctions. nameOfConference
DOI: 10.1039/c7cp06237k
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Li Y, Holloway GW, Benjamin SC et al. (2017). Double quantum dot memristor. nameOfConference
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Puczkarski P, Swett JL, Mol JA (2017). Graphene nanoelectrodes for biomolecular sensing. nameOfConference
DOI: 10.1557/jmr.2017.256
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Sarwat SG, Gehring P, Rodriguez Hernandez G et al. (2017). Scaling Limits of Graphene Nanoelectrodes.. nameOfConference
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Gehring P, Sowa JK, Cremers J et al. (2017). Distinguishing Lead and Molecule States in Graphene-Based Single-Electron Transistors.. nameOfConference
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Sowa JK, Mol JA, Briggs GAD et al. (2017). Vibrational effects in charge transport through a molecular double quantum dot. nameOfConference
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Li Y, Mol JA, Benjamin SC et al. (2016). Interference-based molecular transistors. nameOfConference
DOI: 10.1038/srep33686
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Gehring P, Sadeghi H, Sangtarash S et al. (2016). Quantum Interference in Graphene Nanoconstrictions. nameOfConference
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Salfi J, Mol JA, Culcer D et al. (2016). Charge-Insensitive Single-Atom Spin-Orbit Qubit in Silicon.. nameOfConference
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Salfi J, Mol JA, Rahman R et al. (2016). Quantum simulation of the Hubbard model with dopant atoms in silicon. nameOfConference
DOI: 10.1038/ncomms11342
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Lau CS, Sadeghi H, Rogers G et al. (2016). Redox-Dependent Franck-Condon Blockade and Avalanche Transport in a Graphene-Fullerene Single-Molecule Transistor. nameOfConference
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Van Der Heijden J, Salfi J, Mol JA et al. (2015). Probing a single acceptor in a silicon nanotransistor. nameOfConference
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Puczkarski P, Gehring P, Lau CS et al. (2015). Three-terminal graphene single-electron transistor fabricated using feedback-controlled electroburning. nameOfConference
DOI: 10.1063/1.4932133
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Mol JA, Salfi J, Rahman R et al. (2015). Interface-induced heavy-hole/light-hole splitting of acceptors in silicon. nameOfConference
DOI: 10.1063/1.4921640
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Sadeghi H, Mol JA, Lau CS et al. (2015). Conductance enlargement in picoscale electroburnt graphene nanojunctions. nameOfConference
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Mol JA, Lau CS, Lewis WJM et al. (2015). Graphene-porphyrin single-molecule transistors. nameOfConference
DOI: 10.1039/c5nr03294f
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Lau CS, Mol JA, Warner JH et al. (2014). Nanoscale control of graphene electrodes. nameOfConference
DOI: 10.1039/c4cp03257h
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Zemen J, Mašek J, Ku¿era J et al. (2014). Comparative study of tight-binding and ab initio electronic structure calculations focused on magnetic anisotropy in ordered CoPt alloy. nameOfConference
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Van Der Heijden J, Salfi J, Mol JA et al. (2014). Probing the spin states of a single acceptor atom. nameOfConference
DOI: 10.1021/nl4047015
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Salfi J, Mol JA, Rahman R et al. (2014). Spatially resolving valley quantum interference of a donor in silicon. nameOfConference
DOI: 10.1038/nmat3941
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Miwa JA, Mol JA, Salfi J et al. (2013). Transport through a single donor in p-type silicon. nameOfConference
DOI: 10.1063/1.4816439
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Mol JA, Salfi J, Miwa JA et al. (2013). Interplay between quantum confinement and dielectric mismatch for ultrashallow dopants. nameOfConference
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Fresch B, Verduijn J, Mol JA et al. (2012). Querying a quasi-classical Oracle: One-bit function identification problem implemented in a single atom transistor. nameOfConference
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Mol JA, Van Der Heijden J, Verduijn J et al. (2011). Balanced ternary addition using a gated silicon nanowire. nameOfConference
DOI: 10.1063/1.3669536
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Mol JA, Verduijn J, Levine RD et al. (2011). Integrated logic circuits using single-atom transistors. nameOfConference
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Yan Y, Mol JA, Verduijn J et al. (2010). Electrically addressing a molecule-like donor pair in silicon: An atomic scale cyclable full adder logic. nameOfConference
DOI: 10.1021/jp103524d
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Johnson BC, Tettamanzi GC, Yang C et al. (2010). Single ion implantation into Si-based devices. nameOfConference
DOI: 10.1149/1.3485692
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Johnson BC, Tettamanzi GC, Alves ADC et al. (2010). Drain current modulation in a nanoscale field-effect-transistor channel by single dopant implantation. nameOfConference
DOI: 10.1063/1.3458783
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Mol JA, Beentjes SPC, Rogge S (2010). A low temperature surface preparation method for STM nano-lithography on Si(1 0 0). nameOfConference
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Klein M, Mol JA, Verduijn J et al. (2010). Ternary logic implemented on a single dopant atom field effect silicon transistor. nameOfConference
DOI: 10.1063/1.3297906
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Klein M, Lansbergen GP, Mol JA et al. (2009). Reconfigurable logic devices on a single dopant atom - Operation up to a full adder by using electrical spectroscopy. nameOfConference
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Li Z, Mol JA, Lagae L et al. (2008). Pulsed field induced magnetization switching in (Ga,Mn)As. nameOfConference
DOI: 10.1063/1.2900965
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