posted on 2008-02-04, 00:00authored byYi Liu, Ling Chen, Li-Ming Wu, George H. Chan, Richard P. Van Duyne
A series of new quaternary semiconductor materials CsLnCdTe3 (Ln = La, Pr, Nd, Sm, Gd−Tm, and Lu) was
obtained from high-temperature solid-state reactions by the reactive halide flux method. These compounds belong
to the layered KZrCuS3 structure type and crystallize in the orthorhombic space group Cmcm (No. 63). Their
structure features two-dimensional ∞2[LnCdTe3-] layers of edge- and vertex-sharing LnTe6 octahedra with Cd atoms
filling the tetrahedral interstices, which stack along b-axis. The Cs atoms are located between the ∞2[LnCdTe3-]
layers and are surrounded by eight Te atoms to form a CsTe8 bicapped trigonal prism. Such Te layers are more
flexible than the Se analogues in the isostructural CsLnMSe3 to accommodate nearly the entire Ln series. Theoretical
studies performed on CsTmCdTe3 show that the material is a direct band gap semiconductor and agrees with the
result from a single-crystal optical absorption measurement. Magnetic susceptibility measurements show that the
CsLnCdTe3 (Ln = Pr, Nd, Gd, Dy, Tm) materials exhibit temperature-dependent paramagnetism and obey the
Curie−Weiss law, whereas CsSmCdTe3 does not.