A series of compounds, K2RE2Bi2Se9 (RE=La, Ce, Yb), were synthesized using a molten flux, K2Se2, and the elements at 750�C. Single crystal x-ray diffraction of these black, small bandgap materials indicated a slight structural transition that resulted in solutions in two different space groups. The Lanthanum analog solved in the centrosymmetric Pbam space group, whereas the Ce,  Yb analogs solved in the noncentrosymmetric P21212 space group. SQUID magnetic studies showed temperature independent paramagnetism (TIP) in all three compounds.  The La analog was diamagnetic under high fields, while the Ce and Yb analogs exhibited Curie-Weiss paramagnetism. These materials could have the properties required for thermoelectric materials: low thermal conductivity and high electrical conductivity. The compounds have complex anisotropic structures composed of heavy elements that could potentially disrupt phonon translation. The small bandgap and the presence of TIP could indicate these materials could be intrinsic n-type semiconductors.

Structural studies and magnetic properties of the K2RE2Bi2Se9 series (RE=La, Ce, Yb) as potential thermoelectric materials

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.