Physica E Special Issue

“Recent activity about Topological insulators, superconductors and Majorana fermions”

Guest EditorDepartment of Applied Physics, Nagoya University, Yukio Tanaka

Topology is an important concept for the classification of shape by continuous deformation. This concept has been applied to characterize the quantum phases of electronic systems. Well known examples of quantum phenomena characterized by topology is quantum Hall (fractional quantum Hall) system. In this system, the edge current due to the broken time reversal symmetry is protected by the topological invariant defined in the bulk Hamiltonian. A recent breakthrough is the discovery of quantum spin Hall state in 2D and topological insulator in 3D. In these systems, time reversal symmetry (TRS) is not broken and edge states with TRS are protected due to the bulk-edge correspondence, where the bulk Hamiltonian has a topological invariant. It has been also clarified that there are corresponding topological objects in the world of superconductivity. Superconductor with non-trivial Andreev bound states (ABS) which are protected by bulk-edge correspondence are called topological superconductor now. The most dramatic feature is that the emergence of Majorana fermion is an ABS.

In this special issue, we focus on the recent activity about topological insulators, topological superconductors and Majorana fermions. Novel exotic properties and possible functionality of electronic devices are expected to be born from these systems. It is really a new direction of condensed matter nano science and surface science.

[Key word]Topological insulatorEdge stateTopological superconductorAndreev bound stateMajorana fermionNon Abelian statistics