Mapping the relationship between two quantum effects known as topological insulators

At very low temperatures and under strong magnetic fields, thin films of semiconducting materials can display a phenomenon known as the quantum Hall (QH) effect, which can allow electrons to flow with no energy loss. In a newly discovered class of materials known as topological insulators, the same state can be achieved without an external magnetic field, spurring interest in the development of low-power electronics and other promising applications.