First systematic band-filling control in organic conductors.
First systematic band-filling control in organic conductors.
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有机导体中第一个系统的能带填充控制。
DOI：
10.1021/ja010567v
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发表时间：
2002
影响因子：
15
通讯作者：
H. Moriyama
中科院分区：
文献类型：
--
作者：
H. Mori;M. Kamiya;M. Haemori;H. Suzuki;Shōji Tanaka;Y. Nishio;K. Kajita;H. Moriyama
系统地研究了四种不同基态的有机导体的能带填充控制。(1)用（MCl（4））（2-）[M = Co，Zn]部分取代阴离子阻挡层中的（GaCl（4））（-），得到了单晶体[x = 0.0，0.05，0.06]。通过掺杂到具有有效半填充带（x = 0.0）的反铁磁体，室温下的电阻率从3 Ω cm（x = 0.0）降低到0.1 Ω cm（x = 0.06）。(2)另一种2：1（供体/阴离子）盐，δ ′-ET（2）（GaCl（4））（-），其是自旋隙材料，已被掺杂为δ ′-ET（2）（GaCl（4））（-）（1-x）（MCl（4））（2-）（x）[x = 0.05，0.14]。电阻率从10 Ω cm（x = 0.0）降低到0.3 Ω cm（x = 0.14）。对于两种2：1盐，通过掺杂，半导体行为已经转移到相对导电的半导体行为。(3)对于α型3：1盐，母体材料处于电荷有序状态，例如α-（ET（+）ET（+）ET（0））（CoCl（4））（2-）（TCE），其中电荷有序供体分散在二维导电层中。虽然α-ET（3）（CoCl（4））（2-）（TCE）的计算显示出带绝缘性质，并且晶体结构分析表明该材料处于电荷有序状态，但已观察到低至165 K的金属行为。在α-体系中掺入（GaCl（4））（-），得到了等结构的α-ET（3）（CoCl（4））（2-）（1-x）（GaCl（4））（-）（x）（TCE）[x = 0.54，0.57，0.62]，其中水平条纹型电荷有序模式随x的增加而改变。(4)通过将（GaCl（4））（-）掺杂到与β ′-ET（3）（MCl（4））（2）（2-）[M = Zn，Mn]同构的3：2无带隙绝缘体中，得到的β ′-ET（3）（CoCl（4））（2-）（2-x）（GaCl（4））（-）（x）[x = 0.66，0.88]分别在低至100和140 K下显示出金属行为。它们是有机导体中的第一金属态，由无带隙带绝缘体的带填充控制。这些能带填充控制的系统研究表明，掺杂到具有伪1/2填充带的无带隙绝缘体是最有效的。
The systematic study of band-filling control for four kinds of organic conductors with various kinds of ground states has succeeded. (1) By partial substitution of (GaCl(4))(-) by (MCl(4))(2-) [M = Co, Zn] in the anion blocking layer of lambda-ET(2)(GaCl(4))(-) [ET = bis(ethylenedithio)tetrathiafulvalene], single crystals of lambda-ET(2)(GaCl(4))(-)(1-x)(MCl(4))(2-)(x) [x = 0.0, 0.05, 0.06] have been obtained. The resistivity at room temperature decreases from 3 Omega cm (x = 0.0) to 0.1 Omega cm (x = 0.06) by doping to the antiferromagnet with an effective half-filled band (x = 0.0). (2) Another 2:1 (donor/anion) salt, delta'-ET(2)(GaCl(4))(-), which is a spin gap material, has been doped as delta'-ET(2)(GaCl(4))(-)(1-x)(MCl(4))(2-)(x) [x = 0.05, 0.14]. The resistivity is lowered from 10 Omega cm (x = 0.0) to 0.3 Omega cm (x = 0.14). For both 2:1 salts, the semiconducting behaviors have transferred to relatively conductive semiconducting ones by doping. (3) As for alpha-type 3:1 salts, the parent material is in a charge-ordering state such as alpha-(ET(+)ET(+)ET(0))(CoCl(4))(2-)(TCE), where the charge-ordered donors are dispersed in the two-dimensional conducting layer. Although the calculation of alpha-ET(3)(CoCl(4))(2-)(TCE) shows a band-insulating nature, and the crystal structure analysis indicates that this material is in a charge-ordering state, the metallic behavior down to 165 K has been observed. With doping of (GaCl(4))(-) to the alpha-system, isostructural alpha-ET(3)(CoCl(4))(2-)(1-x)(GaCl(4))(-)(x)(TCE) [x = 0.54, 0.57, 0.62] have been afforded, where the pattern of the horizontal stripe-type charge ordering changes with an increase of x. (4) By doping (GaCl(4))(-) to the 3:2 gapless band insulator which is isostructural to beta'-ET(3)(MCl(4))(2)(2-) [M = Zn, Mn], the obtained beta'-ET(3)(CoCl(4))(2-)(2-x)(GaCl(4))(-)(x) [x = 0.66, 0.88] shows metallic behavior down to 100 and 140 K, respectively. They are the first metallic states in organic conductors by band-filling control of the gapless band insulator. These systematic studies of band-filling control suggest that the doping to the gapless band insulator with a pseudo-1/2-filled band is most effective.