Quantum-Dot Heat Engines
Josefsson, Martin LU
(2020)
- Abstract
- This thesis explores the possibilities of using quantum dots (QDs) in nanoscale energy har- vesters converting heat into electrical energy, i.e. heat engines. From a theory perspective, these possibilities have been investigated for almost two decades, and interest in them seem to continuously increase over time. However, a high degree of experimental control over the manufacturing and operation of QD engines have only recently been achieved. This opens up the possibility of verifying the theory predictions and brings new questions to be answered, which is where this thesis aims at making a contribution. The author’s contributions to the work that the thesis builds upon are theoretical, but are often used together with experimental results... (More)
- This thesis explores the possibilities of using quantum dots (QDs) in nanoscale energy har- vesters converting heat into electrical energy, i.e. heat engines. From a theory perspective, these possibilities have been investigated for almost two decades, and interest in them seem to continuously increase over time. However, a high degree of experimental control over the manufacturing and operation of QD engines have only recently been achieved. This opens up the possibility of verifying the theory predictions and brings new questions to be answered, which is where this thesis aims at making a contribution. The author’s contributions to the work that the thesis builds upon are theoretical, but are often used together with experimental results for synergistic effects.
The thesis starts with an introduction to relevant concepts in classical thermodynamics and a quantum mechanical description of electron states in QDs. This is followed by a discus- sion of electron transport in QDs, as well as an introduction to the master equation based approaches used to model the relevant experimental devices.
There are three studies included in the thesis, all of which have been peer-reviewed and published in scientific journals. The details of the physics relevant for each one are presen- ted together with a summary of the studies. The first is an investigation of the performance limits of an experimental implementation of a steady-state QD heat engine, in which the Curzon-Ahlborn efficiency is observed at maximum power and the highest efficiency was in excess of 70% of the Carnot efficiency. This is the first verification that QDs can be used in high efficiency heat engines. The second study investigates how to practically optimize the output power of similar devices, and quantifies how high efficiency one can hope to reach in other implementations of QD engines. The third study proposes an experimental quantum engine based on a double QD where entangled singlet spin states are used to drive the engine. This can be viewed as entanglement acting as the engine’s fuel. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/491e4d17-32e3-47b8-8485-058baa68d1f8
- author
- Josefsson, Martin
LU
- supervisor
-
- Martin Leijnse LU
- Andreas Wacker LU
- opponent
-
- Prof. Pekola, Jukka, Aalto University, Finland.
- organization
- publishing date
- 2020-04-24
- type
- Thesis
- publication status
- published
- subject
- keywords
- quantum dot, heat engine, thermoelectric, quantum thermodynamics, quantum transport, Fysicumarkivet A:2020:Josefsson
- publisher
- Department of Physics, Lund University
- defense location
- Lecture hall Rydbergsalen, Fysicum, Sölvegatan 14, Faculty of Engineering LTH, Lund University, Lund. Follow online: https://youtu.be/IPTyWmMSbSs
- defense date
- 2020-05-20 9:15:00
- external identifiers
-
- scopus:85086804748
- ISBN
- 978-91-7895-497-1
- 978-91-7895-496-4
- project
- Quantum-Dot Heat Engines
- language
- English
- LU publication?
- yes
- id
- 491e4d17-32e3-47b8-8485-058baa68d1f8
- date added to LUP
- 2020-04-08 14:09:14
- date last changed
- 2024-09-18 21:48:57
@phdthesis{491e4d17-32e3-47b8-8485-058baa68d1f8,
abstract = {{This thesis explores the possibilities of using quantum dots (QDs) in nanoscale energy har- vesters converting heat into electrical energy, i.e. heat engines. From a theory perspective, these possibilities have been investigated for almost two decades, and interest in them seem to continuously increase over time. However, a high degree of experimental control over the manufacturing and operation of QD engines have only recently been achieved. This opens up the possibility of verifying the theory predictions and brings new questions to be answered, which is where this thesis aims at making a contribution. The author’s contributions to the work that the thesis builds upon are theoretical, but are often used together with experimental results for synergistic effects.<br/><br/>The thesis starts with an introduction to relevant concepts in classical thermodynamics and a quantum mechanical description of electron states in QDs. This is followed by a discus- sion of electron transport in QDs, as well as an introduction to the master equation based approaches used to model the relevant experimental devices.<br/><br/>There are three studies included in the thesis, all of which have been peer-reviewed and published in scientific journals. The details of the physics relevant for each one are presen- ted together with a summary of the studies. The first is an investigation of the performance limits of an experimental implementation of a steady-state QD heat engine, in which the Curzon-Ahlborn efficiency is observed at maximum power and the highest efficiency was in excess of 70% of the Carnot efficiency. This is the first verification that QDs can be used in high efficiency heat engines. The second study investigates how to practically optimize the output power of similar devices, and quantifies how high efficiency one can hope to reach in other implementations of QD engines. The third study proposes an experimental quantum engine based on a double QD where entangled singlet spin states are used to drive the engine. This can be viewed as entanglement acting as the engine’s fuel.}},
author = {{Josefsson, Martin}},
isbn = {{978-91-7895-497-1}},
keywords = {{quantum dot; heat engine; thermoelectric; quantum thermodynamics; quantum transport; Fysicumarkivet A:2020:Josefsson}},
language = {{eng}},
month = {{04}},
publisher = {{Department of Physics, Lund University}},
school = {{Lund University}},
title = {{Quantum-Dot Heat Engines}},
url = {{https://lup.lub.lu.se/search/files/78199011/Martin_Josefsson.pdf}},
year = {{2020}},
}