Nonlinear Imaging of Nanoscale Topological Corner States

Corner states of topological fullerenes

The unusual electronic properties of the quantum spin Hall or Chern insulator become manifest in the form of robust edge states when samples with boundaries are studied. In this work, we ask if and how the topologically nontrivial electronic structure of these two-dimensional systems can be passed on to their zero-dimensional relatives, namely, fullerenes or other closed-cage molecules. To addr...

NMR probe of metallic states in nanoscale topological insulators.

A 125Te NMR study of bismuth telluride nanoparticles as a function of particle size revealed that the spin-lattice relaxation is enhanced below 33 nm, accompanied by a transition of NMR spectra from the single to the bimodal regime. The satellite peak features a negative Knight shift and higher relaxivity, consistent with core polarization from p-band carriers. Whereas nanocrystals follow a Kor...

Nanoscale β-nuclear magnetic resonance depth imaging of topological insulators.

Considerable evidence suggests that variations in the properties of topological insulators (TIs) at the nanoscale and at interfaces can strongly affect the physics of topological materials. Therefore, a detailed understanding of surface states and interface coupling is crucial to the search for and applications of new topological phases of matter. Currently, no methods can provide depth profili...

Mapping plasmonic topological states at nanoscale. Supplementary information

Imaging topological edge states in silicon photonics

Topological features—global properties not discernible locally—emerge in systems ranging from liquid crystals to magnets to fractional quantum Hall systems. A deeper understanding of the role of topology in physics has led to a new class of matter—topologically ordered systems. The best known examples are quantum Hall effects, where insensitivity to local properties manifests itself as conducta...