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On the Properties of a Few Electron-Hole system in a Double One-dimensional Harmonic Trap

Pan, Fan LU (2012) FYSM31 20122
Department of Physics
Mathematical Physics
Abstract
One of the most important concepts in condensed matter physics is that of ``quasi particles''. The exciton is one such quasi particle. In semi-conductors, excitons are formed by the excitation of electrons from valence band to conduction band, which creates holes in the valence band. Because of the Coulomb force, the electron and the hole are attracted to each other and can form a ``hydrogen-like'' bound state called the exciton.

One notable property of excitons is that they are composite bosons. Bosons are known to form condensates, as was predicted already in mid 1920's (Bose-Einstein condensation, BEC). Such condensates manifest themselves in phenomena such as superfluidity and superconductivity. A question which has often been... (More)
One of the most important concepts in condensed matter physics is that of ``quasi particles''. The exciton is one such quasi particle. In semi-conductors, excitons are formed by the excitation of electrons from valence band to conduction band, which creates holes in the valence band. Because of the Coulomb force, the electron and the hole are attracted to each other and can form a ``hydrogen-like'' bound state called the exciton.

One notable property of excitons is that they are composite bosons. Bosons are known to form condensates, as was predicted already in mid 1920's (Bose-Einstein condensation, BEC). Such condensates manifest themselves in phenomena such as superfluidity and superconductivity. A question which has often been raised in the literature is: do excitations form condensates.

The issue of exciton condensate is more relevant today than ever before because a great deal of progress has been made in experimental techniques for producing condensates. Since 1995 one has been able to produce condensates of several different kinds of atoms, such as Rb, Na, Cs, Ca, and even hydrogen. These methods give a new hope for a more successful production and study of exciton condensates.

One major problem with excitons is their short lifetimes while in order to be able to detect and study their condensates their lifetime should preferably be longer than the cooling time. The electron and the hole tend to recombine and emit light. For recent experiments focus on semiconductor structures with two coupled parallel quantum wells, namely "indirect" excitons. The point is that these excitons can be made to have much longer lifetimes by increasing the strength of the applied electric field. (Less)
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author
Pan, Fan LU
supervisor
organization
alternative title
On the Properties of an Exciton-like Few body System
course
FYSM31 20122
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Electron-Hole system, Few-body, CI methods, Exciton-like, Double one-dimension, harmonic trap
report number
Lund-MPh-12/08
language
English
id
3131351
date added to LUP
2012-11-16 16:33:31
date last changed
2015-12-14 13:32:32
@misc{3131351,
  abstract     = {One of the most important concepts in condensed matter physics is that of ``quasi particles''. The exciton is one such quasi particle. In semi-conductors, excitons are formed by the excitation of electrons from valence band to conduction band, which creates holes in the valence band. Because of the Coulomb force, the electron and the hole are attracted to each other and can form a ``hydrogen-like'' bound state called the exciton.

One notable property of excitons is that they are composite bosons. Bosons are known to form condensates, as was predicted already in mid 1920's (Bose-Einstein condensation, BEC). Such condensates manifest themselves in phenomena such as superfluidity and superconductivity. A question which has often been raised in the literature is: do excitations form condensates.

The issue of exciton condensate is more relevant today than ever before because a great deal of progress has been made in experimental techniques for producing condensates. Since 1995 one has been able to produce condensates of several different kinds of atoms, such as Rb, Na, Cs, Ca, and even hydrogen. These methods give a new hope for a more successful production and study of exciton condensates.

One major problem with excitons is their short lifetimes while in order to be able to detect and study their condensates their lifetime should preferably be longer than the cooling time. The electron and the hole tend to recombine and emit light. For recent experiments focus on semiconductor structures with two coupled parallel quantum wells, namely "indirect" excitons. The point is that these excitons can be made to have much longer lifetimes by increasing the strength of the applied electric field.},
  author       = {Pan, Fan},
  keyword      = {Electron-Hole system,Few-body,CI methods,Exciton-like,Double one-dimension,harmonic trap},
  language     = {eng},
  note         = {Student Paper},
  title        = {On the Properties of a Few Electron-Hole system in a Double One-dimensional Harmonic Trap},
  year         = {2012},
}