h/e oscillations in interlayer transport of delafossites
Microstructures can be carefully designed to reveal the quantum phase of the wave-like
nature of electrons in a metal. Here, we report phase-coherent oscillations of out-of-plane
magnetoresistance in the layered delafossites PdCoO2 and PtCoO2. The oscillation period is
equivalent to that determined by the magnetic flux quantum, h/e, threading an area defined
by the atomic interlayer separation and the sample width, where h is Planck’s constant and e
is the charge of an electron. The phase of the electron wave function appears robust over
length scales exceeding 10 micrometers and persisting up to temperatures of T > 50 kelvin.
We show that the experimental signal stems from a periodic field modulation of the
out-of-plane hopping. These results demonstrate extraordinary single-particle quantum
coherence lengths in delafossites.
12 June 2020