New classes of topological crystalline insulators having surface rotation anomaly
(PHYSorg.com Physics)

In a new report on Science Advances, Chen Fang and Liang Fu from the Beijing National Laboratory for Condensed Matter Physics in China, Kavli Institute for Theoretical Sciences and the Department of Physics, Massachusetts Institute of Technology in the U.S. Detailed the discovery of new types of quantum anomalies in two-dimensional systems with time-reversal symmetry (T) (conservation of entropy) and discrete rotation symmetry; where a shape retains the same structure after rotation by a partial turn and order. They then physically realized anomalous states on the surface of new classes of topological crystalline insulators (TCIs) normal to the rotation axis and supporting a helical mode. The presence of helical modes allowed them to form a new quantum device from a topological crystalline insulator known as a helical nanorod with quantized longitudinal conductance.