Super-geometric electron focusing on the hexagonal Fermi surface of PdCoO${}_2$

Abstract

Geometric electron optics may be implemented in solid state when transport is ballistic on the length scale of a device. Currently, this is realized mainly in 2D materials characterized by circular Fermi surfaces. Here we demonstrate that the nearly perfectly hexagonal Fermi surface of PdCoO2 gives rise to highly directional ballistic transport. We probe this directional ballistic regime in a single crystal of PdCoO2 by use of focused ion beam (FIB) micro-machining, defining crystalline ballistic circuits with features as small as 250nm. The peculiar hexagonal Fermi surface naturally leads to electron self-focusing effects in a magnetic field, well below the geometric limit associated with a circular Fermi surface. This super-geometric focusing can be quantitatively predicted for arbitrary device geometry, based on the hexagonal cyclotron orbits appearing in this material. These results suggest a novel class of ballistic electronic devices exploiting the unique transport characteristics of strongly faceted Fermi surfaces.

References in corpus (16)

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Cited by in corpus (15)

• Optical Excitations with Electron Beams: Challenges and Opportunities
• Directional ballistic transport in the two-dimensional metal PdCoO2
• $h/e$ Oscillations in Interlayer Transport of Delafossites
• Quasiparticle interference and quantum confinement in a correlated Rashba spin-split 2D electron liquid
• Probing the Hall Voltage in Synthetic Quantum Systems
• Low-symmetry non-local transport in microstructured squares of delafossite metals
• Metallic delafossite thin films for unique device applications
• Determination of the phase coherence length of PdCoO${}_2$ nanostructures
• Stripe magnetic order and field-induced quantum criticality in the perfect triangular-lattice antiferromagnet CsCeSe${}_2$
• Anisotropic Scattering in Goniopolar Metal NaSn${}_2$As${}_2$
• Specular electron focusing between gate-defined quantum point contacts in bilayer graphene
• Fully two-dimensional incommensurate charge modulation on the Pd-terminated polar surface of PdCoO2
• Bloch-Lorentz magnetoresistance oscillations in delafossites
• Controlling superconductivity of CeIrIn${}_5$ microstructures by substrate selection
• Disorder-enhanced effective masses and deviations from Matthiessen's rule in PdCoO${}_2$ thin films