Investigation of the bulk band structure of IV-VI compound semiconductors: PbSe and PbTe

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Abstract
The bulk band structure of the IV-VI semiconductors PbSe and PbTe was determined experimentally through angle-resolved photoemission from cleaved PbSe(100) and PbTe(100) surfaces, using synchrotron radiation for photoexcitation. By analyzing spectra recorded in electron emission normal to the surface over a wide range of photon energies, it was found that a large number of photoemission peaks showed dispersion with photon energy, proving that the spectra can be interpreted through direct (i.e., k-conserving) transitions. We analyze the dispersion in terms of transitions from occupied to unoccupied bands, on the basis of the free-electron final-state model. In order to relate the experimental data to calculated band structures, we have carried out linearized muffin-tin-orbital calculations for both solids. The experimental occupied band structure shows excellent agreement with these calculations. We discuss our results in the light of previous experimental and theoretical studies of these materials.