Structures by Peierls Distortions Tellurium

From the perspective of a materials scientist, tellurium is certainly the most attractive element, and it has found applications mainly in the electronics industry because of its p-type semiconducting properties. It can also be used for the synthesis of so-called II-VI semiconductors (such as MgTe) or may be alloyed to yield superior intermetallic phases. In addition, some Te alloys are under investigation in the realm of phase-change media for rapid data storage [273]. 

As we will show in the sequel, this very structure may be understood to arise from a flzree-dimensional Peierls distortion away from a simple cubic structure. Although Peierls theory (see Section 2.6.2) is one-dimensional in its original formulation, there have been extensions to real systems in which two-and three-dimensional cases of Peierls-like distortion were observed. For ex- 

5) lUPAC recommends to call it group 16 whether this is easier to memorize is left to the reader. 

Although this simple cubic phase is unknown for Te, the structurally closely related rhombohedral Te(lV) phase with the [jS-Po] structure (stable between 11 and 27 GPa) exhibits just such an octahedral Te coordination where all six nearest-neighbor distances are equal [276]. This finding may be looked upon as a reminiscence of the pressure-homologue rule of crystal chemistry [5], namely that, under pressure, an element tends to adopt the structure of its higher homologues. 

This little compilation could probably continue forever. However, we can summarize by noting that, whenever possible, nature tries to get rid of antibonding states, for example, by distorting high-symmetry atomic configurations. If that does not work, then there is a problem. 

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