ABSTRACT
Majorana zero modes are leading candidates for topological quantum computation due to non-local qubit encoding and non-abelian exchange statistics. Spatially separated Majorana modes are expected to allow phase-coherent single-electron transport through a topological superconducting island via a mechanism referred to as teleportation. Here we experimentally investigate such a system by patterning an elongated epitaxial InAs-Al island embedded in an Aharonov-Bohm interferometer. With increasing parallel magnetic field, a discrete sub-gap state in the island is lowered to zero energy yielding persistent 1e-periodic Coulomb blockade conductance peaks (e is the elementary charge). In this condition, conductance through the interferometer is observed to oscillate in a perpendicular magnetic field with a flux period of h/e (h is Planck's constant), indicating coherent transport of single electrons through the islands, a signature of electron teleportation via Majorana modes.
ABSTRACT
We describe an apparatus which concurrently and independently measures the parameters determining thermoelectric material conversion efficiency: the Seebeck coefficient, thermal conductivity, and electrical resistivity. The apparatus is designed to characterize thermoelectric materials which are technologically relevant for waste heat energy conversion, and may operate from room temperature to 400 °C. It is configured so the heat flux is axially confined along two boron nitride rods of known thermal conductance. The Seebeck coefficient and thermal conductivity are obtained in steady-state using a differential technique, while the electrical resistivity is obtained using a four-point lock-in amplification method. Measurements on the newly developed NIST Seebeck standard reference material are presented in the temperature range from 50 °C to 250 °C.
