Wuenschell, Jeffrey K.
(2015)
Trapping and Transport of Indirect Excitons in Coupled Quantum Wells.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Spatially indirect excitons are optically generated composite bosons with a radiative lifetime sufficient to reach thermal equilibrium. This work explores the physics of indirect excitons in coupled quantum wells in the GaAs/AlGaAs system, specifically in the low-temperature, high-density regime. Particular attention is paid to a technique whereby a spatially inhomogeneous strain field is used as a trapping potential. In the process of modeling the trapping profile in wide quantum wells, dramatic effects due to intersubband coupling were observed at high strain. Experimentally, this regime coincides with the abrupt appearance of a dark population of indirect excitons at trap center, an effect originally suspected to be related to Bose-Einstein condensation. Here, the role of band mixing due to the strain-induced distortion of the crystal symmetry will be explored in detail in the context of this effect.
Experimental studies presented here and in the literature suggest that Bose-Einstein condensation in indirect exciton systems may be difficult to detect with optical means (e.g., coherence measurements, momentum-space narrowing), possibly due to the strong dipole interaction between indirect excitons. Due to similarities between this system and liquid helium, it may be more fruitful to look for transport-related signatures of condensation, such as superfluidity. Here, a method for performing transport measurements on optically generated indirect excitons is also outlined and preliminary results are presented.
Share
Citation/Export: |
|
Social Networking: |
|
Details
Item Type: |
University of Pittsburgh ETD
|
Status: |
Unpublished |
Creators/Authors: |
Creators | Email | Pitt Username | ORCID ![](/images/orcid_id_24x24.png) |
---|
Wuenschell, Jeffrey K. | jkw14@pitt.edu | JKW14 | |
|
ETD Committee: |
|
Date: |
14 January 2015 |
Date Type: |
Publication |
Defense Date: |
2 December 2014 |
Approval Date: |
14 January 2015 |
Submission Date: |
3 December 2014 |
Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
Number of Pages: |
209 |
Institution: |
University of Pittsburgh |
Schools and Programs: |
Dietrich School of Arts and Sciences > Physics |
Degree: |
PhD - Doctor of Philosophy |
Thesis Type: |
Doctoral Dissertation |
Refereed: |
Yes |
Uncontrolled Keywords: |
semiconductor, quantum wells, excitons, BEC, stress, photoluminescence, transport |
Date Deposited: |
14 Jan 2015 18:25 |
Last Modified: |
15 Nov 2016 14:25 |
URI: |
http://d-scholarship.pitt.edu/id/eprint/23767 |
Metrics
Monthly Views for the past 3 years
Plum Analytics
Actions (login required)
![View Item View Item](/style/images/action_view.png) |
View Item |