Electrical Properties of the Square-Antiprismatic Chain Compounds M4Br4Os (M = Y, Er) and M4Te4Z (M = Nb, Ta; Z = Si, Cr, Fe, Co)
Electrical Properties of the Square-Antiprismatic Chain Compounds M4Br4Os (M = Y, Er) and M4Te4Z (M = Nb, Ta; Z = Si, Cr, Fe, Co)
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方形反棱柱链化合物 M4Br4Os（M = Y、Er）和 M4Te4Z（M = Nb、Ta；Z = Si、Cr、Fe、Co）的电性能
DOI：
10.1021/cm00040a014
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
D. Naugle
中科院分区：
文献类型：
--
作者：
K. Ahn;T. Hughbanks;K. Rathnayaka;D. Naugle
用标准的交流和直流四探针技术测量了稀土金属卤化物R[sub 4]Br[sub 4]Os（R = Y，Er）和几种三元碲化物M[sub 4]Te[sub 4]Z（M = Nb，Z = Si，Fe，Co; M = Ta，Z = Si，Cr，Co）在4.2 ~ 350 K温度范围内的电阻率。稀土卤化物R[sub 4]Br[sub 4]Os表现出半导体行为：电导率随温度呈指数增长。Y[sub 4]Br[sub 4]Os和Er[sub 4]Br[sub 4]Os中的导电激活能（E[sub a]）分别为0.16和0.11 eV。Er[sub 4]Br[sub 4]Os在273 K时的电阻率比Y[sub 4]Br[sub 4]Os小2个数量级。这些化合物的行为与计算的能带结构符合雅阁。等电子化合物M[sub 4]Te[sub 4]Si（M = Ta，Nb）在高温下表现为电子导体。Ta[sub 4]Te[sub 4]Si在160 K时电阻率最大，低于60 K时出现宽的金属-绝缘体转变。测量的Ta[sub 4]Te[sub 4]Si的绝对电阻率比其它碲化物高2个数量级。类似物Nb[sub 4]Te[sub 4]Si在280 K附近显示出类似的异常电阻率最大值，并且在低温（[约]60 K）下电阻率逐渐上升，表明半导体基态。以过渡金属为中心的M[sub 4]Te[sub 4]Z化合物在4.2-300 K的温度范围内都表现为简单的金属;在高于4.2 K的温度下看不到金属-绝缘体转变。Nb[sub 4]Te[sub 4]Fe在25 K附近显示出小的电阻率异常。参考文献30篇，10图，2个标签。«少
The resistivities of the rare-earth metal halides, R[sub 4]Br[sub 4]Os (R = Y, Er) and several of the ternary tellurides M[sub 4]Te[sub 4]Z (M = Nb, Z = Si, Fe, Co; M = Ta, Z = Si, Cr, Co) were measured using standard four-probe ac and dc techniques at temperatures ranging from 4.2 to 350 K. The rare-earth halides R[sub 4]Br[sub 4]Os show semiconducting behavior: conductivity increases exponentially with temperature. Activation energies (E[sub a]) for conduction in Y[sub 4]Br[sub 4]Os and Er[sub 4]Br[sub 4]Os are 0.16 and 0.11 eV, respectively. The resistivity of Er[sub 4]Br[sub 4]Os is 2 orders of magnitude smaller than that of Y[sub 4]Br[sub 4]Os at 273 K. The behavior of these compounds is in accord with the calculated band structure presented. The isoelectronic compounds M[sub 4]Te[sub 4]Si (M = Ta, Nb) behave as electronic conductors at high temperature. Ta[sub 4]Te[sub 4]Si shows a resistivity maximum at 160 K and below 60 K exhibits a broad metal-insulator transition. The absolute resistivity measured for Ta[sub 4]Te[sub 4]Si is 2 orders of magnitude higher than the other tellurides. The analogue Nb[sub 4]Te[sub 4]Si shows a similar anomalous resistivity maximum near 280 K and at low temperature ([approximately]60 K) exhibitsmore » a gradual rise in resistivity that suggests a semiconducting ground state. Transition-metal-centered M[sub 4]Te[sub 4]Z compounds all behave as simple metals in the temperature range 4.2-300 K; metal-insulator transitions are not seen at temperatures greater than 4.2 K. Nb[sub 4]Te[sub 4]Fe shows a small resistivity anomaly near 25 K. 30 refs., 10 figs., 2 tabs.« less