Sturza Mihai, Malliakas Christos D, Bugaris Daniel E, Han Fei, Chung Duck Young, Kanatzidis Mercouri G
Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
Inorg Chem. 2014 Nov 17;53(22):12191-8. doi: 10.1021/ic502137m. Epub 2014 Oct 31.
A new ternary compound NaCu6Se4 was synthesized from the reaction of Cu in a molten sodium polyselenide flux. The compound crystallizes in trigonal space group R3̅m with a = 4.0465(3) Å and c = 41.493(5) Å. The crystal structure contains flat two-dimensional slabs of (1)/∞[Cu6Se4] with a unique structural arrangement, separated by Na cations. The compound contains mixed valency and has a high conductivity of ∼3 × 10(3) S cm(-1) at room temperature, and exhibits increasing conductivity with decreasing temperature, indicating metallic behavior. A small positive thermopower (4-11 μV K(-1) from 300 to 500 K) and Hall effect measurements indicate p-type transport with a carrier concentration of ∼2.8(3) × 10(21) cm(-3) and a hole mobility of ∼8.75 cm(2) V(-1) s(-1) at 300 K. NaCu6Se4 exhibits temperature-independent Pauli paramagnetism.
通过在熔融的多硒化钠熔剂中使铜发生反应，合成了一种新的三元化合物NaCu6Se4。该化合物结晶于三方空间群R3̅m，a = 4.0465(3) Å，c = 41.493(5) Å。晶体结构包含具有独特结构排列的(1)/∞[Cu6Se4]平面二维层板，由Na阳离子分隔。该化合物具有混合价态，在室温下具有约3×10(3) S cm(-1)的高电导率，并且电导率随温度降低而增加，表明具有金属行为。较小的正热电势（300至500 K时为4 - 11 μV K(-1)）和霍尔效应测量表明，在300 K时为p型输运，载流子浓度约为2.8(3)×10(21) cm(-3)，空穴迁移率约为8.75 cm(2) V(-1) s(-1)。NaCu6Se4表现出与温度无关的泡利顺磁性。
