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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-8710
DTSTART:20240919T150000Z
DTEND:20240919T230000Z
DTSTAMP:20260413T171618Z
LAST-MODIFIED:20240823T144054Z
LOCATION:5310 Chamberlin
SUMMARY:Tunable contributions from charge-rectification and momentum t
 ransfer to 1D Coulomb drag\, R. G. Herb Condensed Matter Seminar\,  Do
 minique Laroche\, University of Florida
DESCRIPTION:Coulomb drag is a powerful tool to probe the interaction b
 etween closely-spaced low-dimensional systems. Historically\, this eff
 ect has been understood in terms of momentum transfer between carriers
  in the two nearby conductors\, resulting in a friction-like effect. I
 n one-dimensional systems\, Coulomb drag is especially helpful\, as si
 ngle wire conductance measurements seldom yield information on the nat
 ure of the Luttinger liquid forming in there strongly confined systems
 . In this talk\, I will present the experimental observation highlight
 ing an alternate drag-inducing mechanism occurring in mesoscopic one-d
 imensional systems: charge rectification. In contrast to momentum tran
 sfer\, whose polarity depends on the drive current direction\, the cha
 rge rectification mechanism consistently generates a drag signal in a 
 given direction\, regardless of the drive current direction. After pre
 senting the signatures of this novel drag-inducing mechanism in latera
 lly-coupled quantum wires\, I will present our studies of Coulomb drag
  in vertically-coupled quantum wires separated by a barrier only 15 nm
  wide. In these vertically coupled devices\, fabricated through an Epo
 xy-Bond-And-Stop-Etch (EBASE) process\, notable contributions from bot
 h momentum transfer and charge rectification are observed simultaneous
 ly. Moreover\, the relative strength of both contributions is tunable 
 through both gate voltage and temperature. Through a careful temperatu
 re dependence study of the drag signal\, we observe a non-monotonic te
 mperature dependence characteristic of Luttinger liquid physics. Furth
 ermore\, we confirm the exponential dependence of Coulomb drag with kf
 d for both charge rectification- and momentum transfer-induced Coulomb
  drag. This study opens up the possibility of studying the physical me
 chanisms behind the onset of both momentum transferred and charge rect
 ified drag simultaneously in a single device\, ultimately leading to a
  better understanding of Luttinger liquids in multi-channel wires and 
 paving the way for the creation of energy harvesting devices.
URL:https://www.physics.wisc.edu/events/?id=8710
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