摘要
According to different structure of electronic states,materials are divided traditionally into two types, namely,'metals'and'insulators'.Topological insulators,however,are new states of quantum matter. It is very different from traditionally defined'metals'and'insulators'.The electronic state of its body is an insulator with energy cap,and its surface is metal state without energy gap.This surface metal
According to different structure of electronic states, materials are divided traditionally into two types, namely, ＂metals＂ and ＂insulators＂. Topological insulators, however, are new states of quantum matter. It is very different from traditionally defined ＂metals＂ and ＂insulators＂. The electronic state of its body is an insulator with energy cap, and its surface is metal state without energy gap. This surface metal state without energy gap is also very different from the surface state in the general sense in that is it due to unsaturated bind on the surface or due to surface reconstruction.
