42 research outputs found
Unconventional spin texture of a topologically nontrivial semimetal Sb(110)
The surfaces of antimony are characterized by the presence of spin-split
states within the projected bulk band gap and the Fermi contour is thus
expected to exhibit a spin texture. Using spin-resolved density functional
theory calculations, we determine the spin polarization of the surface bands of
Sb(110). The existence of the unconventional spin texture is corroborated by
the investigations of the electron scattering on this surface. The charge
interference patterns formed around single scattering impurities, imaged by
scanning tunneling microscopy, reveal the absence of direct backscattering
signal. We identify the allowed scattering vectors and analyze their bias
evolution in relation to the surface-state dispersion.Comment: 10 pages, 5 figure
One-dimensional spin texture of Bi(441): Quantum spin Hall properties without a topological insulator
The high index (441) surface of bismuth has been studied using Scanning
Tunnelling Microscopy (STM), Angle Resolved Photoemission Spectroscopy (APRES)
and spin-resolved ARPES. The surface is strongly corrugated, exposing a regular
array of (110)-like terraces. Two surface localised states are observed, both
of which are linearly dispersing in one in-plane direction (), and
dispersionless in the orthogonal in-plane direction (), and both of which
have a Dirac-like crossing at =0. Spin ARPES reveals a strong in-plane
polarisation, consistent with Rashba-like spin-orbit coupling. One state has a
strong out-of-plane spin component, which matches with the miscut angle,
suggesting its {possible} origin as an edge-state. The electronic structure of
Bi(441) has significant similarities with topological insulator surface states
and is expected to support one dimensional Quantum Spin Hall-like coupled
spin-charge transport properties with inhibited backscattering, without
requiring a topological insulator bulk
An Organic Spin Crossover Material in Water from a Covalently Linked Radical Dyad
A covalently linked viologen radical cation dyad acts as a reversible thermomagnetic switch in water. Cycling between diamagnetic and paramagnetic forms by heating and cooling is accompanied by changes in optical and magnetic properties with high radical fidelity. Thermomagnetic switches in water may eventually find use as novel biological thermometers and in temperature-responsive organic materials where the changes in properties originate from a change in electronic spin configuration rather than a change in structure