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 Gamma SigmaK-direction wi th the aim of investigating prototype materials for the inverted band struc ture model in detail. The samples were prepared by cleavage of the non pola r (110)-surface plane to minimize the effects of surface charges. Assuming free electron parabola for the final states and considering reciprocal umkl app vectors the bulk band structure of the complete valence band was determ ined. This enabled a comparison to a state of the art-theoretical band stru cture calculation and to older experimental results obtained with different methods. In the case of HgTe with large spin-orbit splitting also the indi vidual Gamma (7), Gamma (6), and Gamma (8)-bands could be resolved at the v alence band maximum, confirming the model of the inverted band structure di rectly. An attempt was made to apply this direct method also to HgSe. (C) 2 001 Elsevier Science BY All rights reserved.