Low-energy electron diffraction and microscopy studies of Fe5GeTe2*

The magnetic properties of van der Waals magnets can be altered by tuning their lattice structure with different stacking orders, opening up new opportunities for exploring spintronic applications. Fe5GeTe2 has recently emerged as a new member in Fe-Ge-Te system with near room temperature ferromagnetism. It was reported that Fe5GeTe2 has a structural phase transition at 550 K, and thus the lattice structure depends on how the crystal is cooled down. In this talk, we will present low-energy electron diffraction and microscopy (LEED/LEEM) studies of Fe5GeTe2. Our LEEM images demonstrate two types of structural domains in a freshly cleaved Fe5GeTe2 crystal at room temperature. Moreover, the intensity-voltage curves indicate that structural variation between the two domains is very subtle, pointing to a modification of stacking orders. Our results pave the route to future investigations of the connection between magnetic order and lattice structure in Fe5GeTe2