2 research outputs found
Proximity-Induced Superconductivity and Quantum Interference in Topological Crystalline Insulator SnTe Thin-Film Devices
Topological
crystalline insulators represent a new state of matter,
in which the electronic transport is governed by mirror-symmetry protected
Dirac surface states. Due to the helical spin-polarization of these
surface states, the proximity of topological crystalline matter to
a nearby superconductor is predicted to induce unconventional superconductivity
and, thus, to host Majorana physics. We report on the preparation
and characterization of Nb-based superconducting quantum interference
devices patterned on top of topological crystalline insulator SnTe
thin films. The SnTe films show weak anti-localization, and the weak
links of the superconducting quantum interference devices (SQUID)
exhibit fully gapped proximity-induced superconductivity. Both properties
give a coinciding coherence length of 120 nm. The SQUID oscillations
induced by a magnetic field show 2Ï€ periodicity, possibly dominated
by the bulk conductivity
A Universal Scheme to Convert Aromatic Molecular Monolayers into Functional Carbon Nanomembranes
Free-standing nanomembranes with molecular or atomic thickness are currently explored for separation technologies, electronics, and sensing. Their engineering with well-defined structural and functional properties is a challenge for materials research. Here we present a broadly applicable scheme to create mechanically stable carbon nanomembranes (CNMs) with a thickness of ∼0.5 to ∼3 nm. Monolayers of polyaromatic molecules (oligophenyls, hexaphenylbenzene, and polycyclic aromatic hydrocarbons) were assembled and exposed to electrons that cross-link them into CNMs; subsequent pyrolysis converts the CNMs into graphene sheets. In this transformation the thickness, porosity, and surface functionality of the nanomembranes are determined by the monolayers, and structural and functional features are passed on from the molecules through their monolayers to the CNMs and finally on to the graphene. Our procedure is scalable to large areas and allows the engineering of ultrathin nanomembranes by controlling the composition and structure of precursor molecules and their monolayers