Bugaris Daniel E, Malliakas Christos D, Bud'ko Sergey L, Calta Nicholas P, Chung Duck Young, Kanatzidis Mercouri G
Materials Science Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
Inorg Chem. 2017 Dec 4;56(23):14584-14595. doi: 10.1021/acs.inorgchem.7b02389. Epub 2017 Nov 21.
Previously synthesized only as powders, single crystals of the RERuGe (RE = La, Ce, Nd, Gd, Tb) series of compounds have now been obtained from molten In. These materials crystallize with the UCoSi-type structure in orthorhombic space group Ibam with lattice parameters a ≈ 10.00-9.77 Å (La-Tb), b ≈ 12.51-12.35 Å, and c ≈ 5.92-5.72 Å. The structure is a three-dimensional framework consisting of RuGe and RuGe units, as well as Ge-Ge zigzag chains. This structure type and those of the other five (ScFeSi, LuCoSi, YRhSn, YbIrGe, and YbPtSn) to compose the RETX phase space are discussed in depth. For the three compounds with RE = Nd, Gd, Tb, multiple magnetic transitions and metamagnetic behavior are observed. Electronic band structure calculations performed on LaRuGe indicate that these materials have a negative band gap and are semimetallic in nature.
此前仅作为粉末合成的RERuGe（RE = La、Ce、Nd、Gd、Tb）系列化合物的单晶，现在已从熔融铟中获得。这些材料在正交空间群Ibam中以UCoSi型结构结晶，晶格参数为a≈10.00 - 9.77 Å（La - Tb），b≈12.51 - 12.35 Å，c≈5.92 - 5.72 Å。该结构是一个由RuGe和RuGe单元以及Ge - Ge之字形链组成的三维框架。深入讨论了这种结构类型以及构成RETX相空间的其他五种（ScFeSi、LuCoSi、YRhSn、YbIrGe和YbPtSn）结构类型。对于RE = Nd、Gd、Tb的三种化合物，观察到了多个磁转变和变磁行为。对LaRuGe进行的电子能带结构计算表明，这些材料具有负带隙，本质上是半金属。
