Lattice structure of FePS3, showing the van der Waals bonded monolayers carrying magnetic moments.
Can less be more? The answer is 'yes', when we compress things and get a result that is beyond our expectations. A new Physical Review Letter on high pressure experiments in FePS3 by Montu's group, with collaborators at Earth Sciences, the Diamond Light Source and the ILL, reports a pressure induced metal insulator transition in a fascinating layered material.
2-Dimensional magnetic materials promise to surpass graphene in a number of ways. We have recently taken a leap towards understanding the dynamic relationship between electronic and structural properties of 'magnetic graphene' that can introduce magnetism to emerging graphene-based technology. For the case of this material, FePS3, an electrical insulator, by applying pressure we were able squash the 2D layers together and switch it into a metal, this is often termed a Mott transition. Magnetism arising from arrangement of electronic spins is exploited in most memory devices and sensors and this is a key constituent for developing technologies like spintronics and spin-caloritronics.
These 2-D materials are characterised by weak mechanical forces between the crystal planes and high pressure (achieved by forcing together two opposed diamonds) hasve the effect of pressing these planes together; gradually and controllably pushing the system from two- to three-dimensionality and simultaneously, from insulator to metal. Our research points to an exciting direction for producing 2-dimensional materials with tunable and conjoined electrical, magnetic and electronic properties. (Montu Saxena, 7/1/19)