Observation of three-dimensional behavior in surface states of bismuth nanowires and the evidence for bulk-Bi surface quasiparticles

We studied trigonal Bi nanowires (30 nm < diameter < 200 nm) via low-temperature magnetotransport for fields up to 14 T in order to investigate the role of their surfaces. A two-dimensional behavior was expected; we found instead a three-dimensional behavior, with a rich spectrum of Landau levels in a nearly spherical Fermi surface. We show that recent observations of sharp peaks in the bulk-Bi Nernst thermopower near the 9 T quantum limit attributed to charge fractionalization, can be more plausibly interpreted in terms of surface states. Bismuth has a true quantum limit at around 70 T.