The layer compound GaSe is characterized by a considerable anisotropy in various physical properties. Easy cleavage occurs, for' example, parallel to the layer, indicating that the cohesion between the layers is relatively weak. The band structure of GaSe has been therefore obtained by Bassani and Pastori /1/ in the single-layer two-dimensional approximation. More recently, a full three-dimensional pseudopotential calculation has been made by Schliiter /2/. In general, the valence bands predicted by these authors a r e similar, but considerable differences appear in the predicted conduction bands. By using the tight-binding approach in the twodimensional approximation and assuming reasonable values for the matrix elements of the crystal Hamiltonian we have obtained the band structure of GaSe which agrees well with Schliiter's data.A layer of GaSe contains four monoatomic sheets in the sequence Se-Ga-Ga-Se with the space group D1 atoms possess three and six valence electrons, respectively. These electrons a r e considered to occupy the s, p closed shell, where p and p orbitals lie in the layer while the p orbitals a r e perpendicular to the layer, The total 18 valence electrons per unit cell occupy nine valence bands in the first Brillouin zone which is hexagonal /3/. A t a general point of this zone, the small point group of the wave vector contains the reflection in the (x, y) plane so that any energy band is always even or odd. W e denote by superscripts
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.