Physicists from five Rice University laboratories and more than a dozen collaborating institutions have discovered a way to use heat to switch crystals of iron, germanium and tellurium between two topological phases where quantum bits of information, or qubits, could potentially be stored. The researchers showed that empty atomic sites in the crystals’ lattice are randomly distributed in one phase (left) and ordered in the other (right). The crystals form under intense heat, and how quickly they cool was shown to determine their phase. To demonstrate, the researchers showed they could switch phases on and off by reheating crystals and allowing them to cool for either longer or shorter periods of time. The result is a change in the crystalline symmetry that dictates the electronic topology.

Credit: Han Wu/Yi Research Group/Rice University.