On the band structure of HgTe and HgSe — view from photoemission

The electronic structure of the Hg-chalcogenides HgTe and HgSe was studied by means of high resolved photoemission along the ??K-direction with the aim of investigating prototype materials for the inverted band structure model in detail. The samples were prepared by cleavage of the non polar (110)-surface plane to minimize the effects of surface charges. Assuming free electron parabola for the final states and considering reciprocal umklapp vectors the bulk band structure of the complete valence band was determined. This enabled a comparison to a state of the art–theoretical band structure calculation and to older experimental results obtained with different methods. In the case of HgTe with large spin–orbit splitting also the individual ?7, ?6, and?8-bands could be resolved at the valence band maximum, confirming the model of the inverted band structure directly. An attempt was made to apply this direct method also to HgSe.