Surface phases on Te (0001) single crystal by low temperature STM

Tellurium has a curious crystal structure where one dimensional covalently bound chains are held together by van der Waals interactions in a hexagonal pattern. Additionally, theory predicts that the (0001) surface (perpendicular to the chains) of tellurium is a candidate to host a zero-energy bound state. Since evaporated thin films tend to grow in the (1000) direction, we use a Te single crystal to examine the (0001) surface by low temperature scanning tunneling microscopy/spectroscopy. The samples were cut from a larger single crystal and chemo-mechanically polished. After introduction into the ultra-high vacuum system the samples were carefully cleaned by Ar ion sputtering and annealing cycles. We found two surface structures as candidates for the native (0001) surface. The first is a row structure with a period of twice the lattice constant hinting at dimerization of the dangling bonds. The second is more complicated with rows separated by terraces of variable width. This might be a higher-index surface or induced by residual contamination . Initial spectroscopy measurements will also be discussed.