Building materials one atomic layer at a time aids the search for exotic phases of matter

A new technique for identifying exotic states of matter in crystalline materials has been demonstrated by RIKEN researchers.

The electrons in some crystalline materials work together to create a host of unusual states, or phases. This collective behavior in these so-called correlated electron materials occurs because the electrons interact with each other via an intrinsic property known as spin, which is related to the rotation of the electrons about their axes. Although correlated electron materials have attracted much interest in the past decade, it has proved difficult to identify the exact mechanisms that give rise to specific phases and to determine what drives a material to switch from one phase to another.

Now, Jobu Matsuno from the RIKEN Advanced Science Institute and his colleagues have investigated these mechanisms in a class of materials called iridates ("Engineering a spin-orbital magnetic insulator by tailoring superlattices"). These materials are interesting because their behavior is predominantly governed by two effects that are roughly equal in magnitude: the repulsive Coulomb force between electrons arising from their electric charge and the spin–orbit interaction, which arises because the spin of an electron interacts with its orbital motion. Theoretical analysis indicates that competition or cooperation between these two effects gives rise to a number of exotic phases in iridates