NOVEL VARIABLE PHASES IN THE QUATERNARY Pb–Bi–Te–Se SYSTEM ALONG THE PbBi2Te4–PbBi2Se4 ISOPLETH SECTION

The phase eqilibria in the Pb–Bi–Te–Se quaternary system along the PbBi2Te4–PbBi2Se4 isopleth section was investigated experimentally using differential thermal analysis and X-ray diffraction analyses of the equilibrated alloys. It was shown that the system is non-quasi-binary one and featured by the formation of the tetradymite-type solid solutions based on the PbBi2Te4 in the wide range of concentration. The system has a more complex phase equilibria scheme that comes from its host reciprocal PbTe–PbSe–Bi2Se3–Bi2Te3 system. One can see that, in order to reveal the phase equilibria scheme and understand the crystallization scheme, reactions types etc., the thorough investigation of the entire pointed reciprocal PbTe–PbSe–Bi2Se3–Bi2Te3 system is very important