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SUMMARY:Hydrodynamic flow of electrons
DTSTART:20161202T151500
DTSTAMP:20260525T190837Z
UID:811a6efe699ad5de80b36b8e4d86f08e062ac0281b7834ad3438dc78
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Philip Moll\, \n\nMax Planck Institute for Chemical Physi
 cs of Solids\, Dresden\, Germany\nHow similar is the flow of electrons in
  a solid to the flow of water in a pipe? Early on physicists envisioned t
 hese processes to be related and this picture prevails in our language (
 “an electric current flows”). However\, this simple fluid analogy fa
 ils to describe the transport of electrons in a wire. The defining propert
 y of liquids is the conservation of momentum\, and the resulting non-line
 ar the Navier-Stokes equations lead to instabilities such as turbulence 
 and vorticity. The analogous situation of static electron flow is typical
 ly much less exciting\, as electrons relax their momentum by frequent co
 llisions with lattice defects and phonons.\n\nRecent experimental and the
 oretical progress has shown hydrodynamic flow to exist in exceptional mat
 erials\, where momentum relaxing collision processes are unusually rare wh
 ile electron-electron scattering occurs at a fast rate. Here\, the electr
 on momentum can be quasi-conserved on a short timescale and hydrodynamic 
 corrections to charge transport can be observed. In our work\, we focus 
 on PdCoO2\, a quasi two-dimensional electronic material[1] with a low tem
 perature mean free path of 20microns.\n\nThe technological key to this ex
 periment is the fabrication of micron-sized structures of highest single 
 crystal quality via Focused Ion Beam etching. This technique enables new 
 types of experiments in crystalline solids\, and some examples will be s
 howcased ranging from challenging experiments under extreme conditions su
 ch as pulsed magnetic field or high pressure in diamond anvil cells to th
 ermodynamic measurements and “crystals by design” in three dimensions
 . In the particular case of hydrodynamic transport\, we fabricate crystal
  channels of different width (80…0.7mm) and observe an unusual scaling 
 of the device resistivity on its cross-section that quantitatively agrees
  with the hydrodynamic predictions of viscous electron flow. Other groups
 [2\,3] have identified key signatures of hydrodynamic conduction in grap
 hene\, based on current flow vorticity and breaking of the Wiedemann-Fran
 z law. Hence electrons in solids can at times indeed resemble this early
  picture of liquids flowing in a pipe[4].\n \nReferences:\n[1] P.J.W.M. e
 t al.\, Science 351\, 1061 (2016)\; \n[2] J. Crossno et al.\, Science 35
 1\, 1058 (2016)\n[3] D.A. Bandurin et al.\, Science 351\, 1055 (2016)\; \
 n[4] J. Zaanen\, Science 351\, 1026 (2016)\n 
LOCATION:CE 1 5 https://plan.epfl.ch/?room==CE%201%205
STATUS:CONFIRMED
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