A criterion to determine the existence of zero-energy edge states is discussed for a class of particle-hole symmetric Hamiltonians. A “loop” in a parameter space is assigned for each one-dimensional bulk Hamiltonian, and its topological properties, combined with the chiral symmetry, play an essential role. It provides a unified framework to discuss zero-energy edge modes for several systems such as fully gapped superconductors, two-dimensional [Formula presented]-wave superconductors, and graphite ribbons. A variance of the Peierls instability caused by the presence of edges is also discussed.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)