Atomic and Electronic Structure of a Multidomain GeTe Crystal.

Renewed interest in the ferroelectric semiconductor germanium telluride was recently triggered by the direct observation of a giant Rashba effect and a 30-year-old dream about a functional spin field-effect transistor. In this respect, all-electrical control of the spin texture in this material in combination with ferroelectric properties at the nanoscale would create advanced functionalities in spintronics and data information processing. Here, we investigate the atomic and electronic properties of GeTe bulk single crystals and their (111) surfaces.

Interstitial defects in the van der Waals gap of BiSe.

BiSe is a thermoelectric material and a topological insulator. It is slightly conducting in its bulk due to the presence of defects and by controlling the defects different physical properties can be fine tuned. However, studies of the defects in this material are often contradicting or inconclusive.

Observation of hidden atomic order at the interface between Fe and topological insulator BiTe.

To realize spintronic devices based on topological insulators (TIs), well-defined interfaces between magnetic metals and TIs are required. Here, we characterize atomically precisely the interface between the 3d transition metal Fe and the TI BiTe at different stages of its formation. Using photoelectron diffraction and holography, we show that after deposition of up to 3 monolayers Fe on BiTe at room temperature, the Fe atoms are ordered at the interface despite the surface disorder revealed by our scanning-tunneling microscopy images.