The notion of three-dimensional topological insulators is extended to systems that host no gapless surface states but exhibit topologically protected gapless hinge states and it is shown that SnTe as well as surface-modified Bi2TeI, BiSe, and BiTe are helical higher-order topology insulators.
A simple prescription to flatten isolated Bloch bands with a nonzero Chern number is presented and perfect flattening can be attained with further range hoppings that decrease exponentially with distance.
It is shown that SrSi2 is a Weyl semimetal even without spin– orbit coupling and that, after the inclusion of spin–orbit coupling, two Weyl fermions stick together forming an exotic double Weylfermion with quadratic dispersions and a higher chiral charge of ±2.
Signs of the Weyl fermion chiral anomaly in the magneto-transport of TaAs are reported and it is observed that high mobility TaAs samples become more conductive as a magnetic field is applied along the direction of the current for certain ranges of the field strength.
The detailed angle-resolved photoemission measurements, first-principles simulations and theoretical topological analysis illustrate the physical mechanism underlying the formation of the topological nodal-line states and associated surface states for the first time, thus paving the way towards exploring the exotic properties of the bottom-line fermions in condensed matter systems.
Theoretical analysis of the experiments suggests a tantalizing unconventional chiral charge density wave in the frustrated kagome lattice, which can not only lead to a large anomalous Hall effect with orbital magnetism, but also be a precursor of unconventional superconductivity.
It is established that the electronic structure of bismuth, an element consistently described as bulk topologically trivial, is in fact topological and follows a generalized bulk–boundary correspondence of higher-order: not the surfaces of the crystal, but its hinges host topologically protected conducting modes.
The bulk-boundary correspondence is directly demonstrated and the topologically nontrivial nature of the Weyl semimetal state in TaP is established, by resolving the net number of chiral edge modes on a closed path that encloses the Wey node.
It is shown that Kramers–Weyl fermions are a universal topological electronic property of all non-magnetic chiral crystals with spin–orbit coupling and are guaranteed by structural chirality, lattice translation and time-reversal symmetry.
This paper uses a fully convolutional neural network model as a variational ansatz to study the frustrated spin-1/2 J1-J2 Heisenberg model on the square lattice and demonstrates that the resulting predictions for both ground-state energies and properties are competitive with, and often improve upon, existing state-of-the-art methods.