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SUMMARY:When the Quantum World Breaks Through and Resistance Becomes Quant
 ized - Sir Michael Pepper FREng FRS - Emeritus Professor of Physics\, Cave
 ndish Laboratory
DTSTART:20231127T180000Z
DTEND:20231127T193000Z
UID:TALK205345@talks.cam.ac.uk
CONTACT:Drishtant Chakraborty
DESCRIPTION:The great power of semiconductor technology is well known for 
 having given us modern Information Technology and all that flows from it. 
 In addition\, modern semiconductor structures can be developed to investig
 ate fundamental aspects of physics which are not accessible using naturall
 y occurring solids. In this talk examples will be given\, in particular th
 e creation of devices where electrons are restricted to one- dimension whe
 n it is found that a quantized staircase appears in which the conductance 
 takes values of 2ne 2 /h\, where n is an integer referring to the number o
 f levels and the factor of 2 arises from the spin degeneracy. One of the c
 haracteristics of many aspects of electron transport in solids is that we 
 can explain results by ignoring the strong repulsion between electrons. In
  one-dimension the mutual interaction can play a dominant role. This is pa
 rticularly the case in considering the transition regime between 1D and 2D
 \, two dimensions\, which until recently was not explored in detail. Howev
 er theory predicts that as the confinement weakens the carriers can move t
 o the sides and adopt a zig-zag configuration to decrease the electron-ele
 ctron repulsion. An unexpected feature of this particular electron configu
 ration is that sometimes the electrons no longer behave as if they had the
  normal charge\, e\, but rather a fraction of that value such as e/5 or 2e
 /5. Simple theoretical concepts will be presented to explain these feature
 s.
LOCATION:Wolfson Lecture Theatre\,  Department of Chemistry\, Lensfield Ro
 ad
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