Electron transport in driven nanojunctions
Nanojunctions offer the possibility of studying the transport properties of driven nano-sized materials, such quantum dots or single molecules, attached to electric leads. Recent experimental and theoretical studies of these systems has increasing our understanding of quantum transport phenomena, th...
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| Tipo de recurso: | tesis de maestría |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | Chile |
| OAI Identifier: | oai:repositorio.anid.cl:10533/253053 |
| Acceso en línea: | https://hdl.handle.net/10533/253053 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Naturales Ciencias Físicas Física Atómica, Molecular y Química |
| Sumario: | Nanojunctions offer the possibility of studying the transport properties of driven nano-sized materials, such quantum dots or single molecules, attached to electric leads. Recent experimental and theoretical studies of these systems has increasing our understanding of quantum transport phenomena, that underlie the behaviour of the building blocks of electronic circuits. In this Thesis, we study the electron transport in nanojunctions. We develop a model in which the nanojunction is treated as an open-quantum system, whit the nano-sized material modelled as a conducting array of electron sites, interacting with multiple environments. We model the nanojunction dynamics with a Lindblad quantum master equation, which takes into account the interactions that induce electron transitions between the conducting array eigenstates. Solving numerically the nanojunction dynamics in the steady state, we compute nanojuction observables such as the electric current through the nanojunction while a bias voltage is applied. Our results show that electron tunneling dynamics explains conductance peak at voltages where a resonant condition is satisfied. Processes such as spontaneous emission or phonon relaxation, explain the behaviour of populations on a set of eigenstates affected by them, producing that their contribution to the current at the left-right contacts are different. Electron transport is dependent on the conducting array geometries, but reaching similar saturation current value. When an incoherent pumping source is applied to the conducting array, our results show the effects of current-induced light and light-induced current, allowing even a photocurrent at zero bias configuration when the left-right tunneling rates are different, while the induced photocurrent direction depends on whether the conducting array has delocalized electrons in the ground or the excited orbital manifold. |
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