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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-1527
DTSTART:20090605T150000Z
DURATION:PT1H0M0S
DTSTAMP:20260422T163511Z
LAST-MODIFIED:20090601T174838Z
LOCATION:5310 Chamberlin
SUMMARY:Electronic refrigeration of two-dimensional electron gases\, R
 . G. Herb Condensed Matter Seminar\, Jon Prance\, Cambridge University
DESCRIPTION:Two-dimensional electron gases (2DEGs) in semiconductors a
 re the basis for studies of a wide range of physical phenomena\, parti
 cularly at sub-kelvin temperatures. However\, efforts to cool these sy
 stems much below 10 mK quickly encounter the problems of reduced therm
 al conductivities and the necessity for increasingly complex refrigera
 tion techniques.<br>
\n<br>
\nOne possible solution is direct electron
 ic refrigeration of the 2DEG. The Quantum Dot Refrigerator (first prop
 osed by Edwards et al.[1]) employs energy-selective tunneling through 
 a pair of quantum dots to cool an otherwise isolated electron gas\, po
 tentially below the temperature of its host lattice. Such a device doe
 s not require specialised fabrication techniques and\, in theory\, can
  operate at arbitrarily low temperatures.<br>
\n<br>
\nIn this talk\, 
 we will present measurements of a Quantum Dot Refrigerator designed to
  cool an isolated 2DEG with an area of 6 square microns [2]. To interp
 ret the results\, a model has been developed which extends previous wo
 rk to the regime of strong electrostatic coupling between the componen
 ts of the device. Within the context of this model\, the data show str
 ong evidence for active cooling. We will discuss the practical limitat
 ions of such devices\, methods for improving performance and evaluatio
 n\, and potential applications.<br>
\n<br>
\n[1] Edwards et al.\, PRB 
 52\, p5714 (1995)<br>
\n[2] Prance et al.\, PRL 102\, 146602 (2009)
URL:https://www.physics.wisc.edu/events/?id=1527
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