Synthesis and spectroscopic study of B20 phase FeGe thin films

The B20 phase transition-metal silicides and germanides host intriguing electronic and magnetic properties. A few examples include the silicides CoSi and RhSi which host topological chiral fermions and surface Fermi arc states, and the germanides MnGe and FeGe which host the magnetic skyrmion states. In particular, the skyrmion ordering temperature in FeGe is close to room temperature, making FeGe a captivating platform for realizing skyrmion spintronics and magnetic memory. Compared with the magnetic properties, the electronic structure of B20 FeGe has been relatively less explored. This partially results from the difficulty in cleaving the crystals due to the cubic structure and covalent bonding. We circumvented this problem by synthesizing B20 FeGe thin films using molecular beam epitaxy and performing in-situ angle-resolved photoemission spectroscopy measurements. We will discuss the synthesis method and spectroscopic results.