Researchers at the University of Jyväskylä and Aalto University in Finland have experimentally realized a two-dimensional topological crystalline insulator, a quantum material predicted more than a decade ago but never before built. The team, led by Associate Professor Kezilbeiek Shawulienu with Professors Peter Liljeroth and Jose Lado, grew two atomically thin layers of tin telluride on a niobium diselenide substrate.
The material shows pairs of conducting edge states protected by the symmetry of its crystal lattice, with an electronic band gap exceeding 0.2 electron volts. Because that gap is relatively large, the topological properties are expected to remain stable even at room temperature — and the edge states can be tuned by applying mechanical strain.
The findings, published in Nature Communications, open a new experimental platform for studying exotic electronic behavior and could point toward practical room-temperature quantum electronics, an application that has so far required extreme cooling in most topological materials.