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Quantum ratchets and quantum heat pumps

Linke, H; Humphrey, TE; Lindelof, PE; Löfgren, Anneli LU ; Newbury, R; Omling, Pär LU ; Sushkov, AO; Taylor, RP and Xu, Hongqi LU (2002) In Applied Physics A: Materials Science & Processing 75(2). p.237-246
Abstract
Quantum ratchets are Brownian motors in which the quantum dynamics of particles induces qualitatively new behavior. We review a series of experiments in which asymmetric semiconductor devices of sub-micron dimensions are used to study quantum ratchets for electrons. In rocked quantum-dot ratchets electron-wave interference is used to create a non-linear voltage response, leading to a ratchet effect. The direction of the net ratchet current in this type of device can be sensitively controlled by changing one of the following experimental variables: a small external magnetic field, the amplitude of the rocking force, or the Fermi energy. We also describe a tunneling ratchet in which the current direction depends on temperature. In our... (More)
Quantum ratchets are Brownian motors in which the quantum dynamics of particles induces qualitatively new behavior. We review a series of experiments in which asymmetric semiconductor devices of sub-micron dimensions are used to study quantum ratchets for electrons. In rocked quantum-dot ratchets electron-wave interference is used to create a non-linear voltage response, leading to a ratchet effect. The direction of the net ratchet current in this type of device can be sensitively controlled by changing one of the following experimental variables: a small external magnetic field, the amplitude of the rocking force, or the Fermi energy. We also describe a tunneling ratchet in which the current direction depends on temperature. In our discussion of the tunneling ratchet we distinguish between three contributions to the non-linear current-voltage characteristics that lead to the ratchet effect: thermal excitation over energy barriers, tunneling through barriers, and wave reflection from barriers. Finally, we discuss the operation of adiabatically rocked tunneling ratchets as heat pumps. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Physics A: Materials Science & Processing
volume
75
issue
2
pages
237 - 246
publisher
Springer
external identifiers
  • wos:000175917400010
  • scopus:0036681116
ISSN
1432-0630
DOI
10.1007/s003390201335
language
English
LU publication?
yes
id
ae1b87dd-d791-4f52-8fdb-f765800306e7 (old id 336347)
date added to LUP
2007-10-31 11:17:38
date last changed
2017-07-30 03:50:50
@article{ae1b87dd-d791-4f52-8fdb-f765800306e7,
  abstract     = {Quantum ratchets are Brownian motors in which the quantum dynamics of particles induces qualitatively new behavior. We review a series of experiments in which asymmetric semiconductor devices of sub-micron dimensions are used to study quantum ratchets for electrons. In rocked quantum-dot ratchets electron-wave interference is used to create a non-linear voltage response, leading to a ratchet effect. The direction of the net ratchet current in this type of device can be sensitively controlled by changing one of the following experimental variables: a small external magnetic field, the amplitude of the rocking force, or the Fermi energy. We also describe a tunneling ratchet in which the current direction depends on temperature. In our discussion of the tunneling ratchet we distinguish between three contributions to the non-linear current-voltage characteristics that lead to the ratchet effect: thermal excitation over energy barriers, tunneling through barriers, and wave reflection from barriers. Finally, we discuss the operation of adiabatically rocked tunneling ratchets as heat pumps.},
  author       = {Linke, H and Humphrey, TE and Lindelof, PE and Löfgren, Anneli and Newbury, R and Omling, Pär and Sushkov, AO and Taylor, RP and Xu, Hongqi},
  issn         = {1432-0630},
  language     = {eng},
  number       = {2},
  pages        = {237--246},
  publisher    = {Springer},
  series       = {Applied Physics A: Materials Science & Processing},
  title        = {Quantum ratchets and quantum heat pumps},
  url          = {http://dx.doi.org/10.1007/s003390201335},
  volume       = {75},
  year         = {2002},
}