Title: Anil Kumar: Polymorphism of thermoelectric TAGS-85
Number: 10/19
Status: Closing date exceeded
Begin: Wednesday, 13.03. 2019, 14:10
Tutor: Vladimír Sechovský
Location: lecture room F2, first floor Ke Karlovu 5

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We have a pleasure to invite you to attend the joint seminar
of the Department of Condensed Matter Physics (DCMP)
and the Materials Growth and Measurement Laboratory (MGML)




Anil Kumar: Polymorphism of thermoelectric TAGS-85

lecture given by:

Anil Kumar

Zernike Institute for Advanced Materials, University of Groningen

The seminar takes place in the lecture room F2 
of the Faculty of Mathematics and Physics, Ke Karlovu 5, Praha 2
on Wednesday, 13.3. 2019 from 14:10 

Vladimír Sechovský
On behalf of the DCMP and MGML


The alloys (GeTe)X(AgSbTe2)1-X (commonly known as TAGS) are among the best high-temperature thermoelectric materials, largely due to their low thermal conductivity. Here we focus on TAGS-85, which is reported to have a transition from a rhombohedral phase to a cubic phase above ~200 °C. We have found a way to stabilize both of these polymorphs at room temperature by careful adjustment of the synthesis conditions. We study the structural properties of both rhombohedral and cubic TAGS-85 as a function of thermal cycling and reveal a much more complex behavior than previously reported, involving transformations to novel layered structures. The thermoelectric properties of both polymorphs will be discussed with respect to their electrical conductivity, Seebeck coefficient and thermal conductivity.