Realization of superconductivity at ambient pressure by band-filling control in kappa-(BEDT-TTF)(2)Cu-2(CN)(3)
Realization of superconductivity at ambient pressure by band-filling control in kappa-(BEDT-TTF)(2)Cu-2(CN)(3)
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DOI：
10.1143/jpsj.65.1340
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发表时间：
1996-05-01
影响因子：
1.7
通讯作者：
Saito, G
中科院分区：
文献类型：
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作者：
Komatsu, T;Matsukawa, N;Saito, G
测量了Kappa-和Kappa '-（BEDT-TTF）（2）Cu-2（CN）（3）的电阻率、热电功率（TEP）、ESR和静态磁化率，并重新检验了基于扩展Huckel方法的能带计算，并与相关BEDT-TTF（ET）盐的结果进行了比较。虽然这些盐的晶体和计算的能带结构在实验误差范围内是相同的，但前者是半导体;相反，后者在环境压力（AP）下是金属。能带计算和自旋磁化率（chi（spin））测量表明，前者盐是一个莫特绝缘体与一个确切的半填充带。虽然kappa-（ET）（2）Cu-2（CN）（3）仅显示ET阳离子自由基的ESR信号，但kappa ′-盐在低于约20 K时显示Cu 2+的额外ESR信号。Cu 2+的含量为总铜原子的88-1200 ppm。发现kappa '-（ET）（2）Cu-2（CN）（3）的金属态和AP处的超导电性是通过用Cu 2+取代Cu+的能带填充控制实现的。
The resistivity, thermoelectric power (TEP), ESR and static susceptibility were measured on kappa- and and kappa'-(BEDT-TTF)(2)Cu-2(CN)(3); also, a band calculation based on an extended Huckel method nas re-examined and the results were compared with those of related BEDT-TTF (ET) salts. Although the crystal- and calculated band structures of these salts are identical within experimental error, the former is a semiconductor; on the contrary, the latter is a metal at ambient pressure (AP). The band calculation and the spin susceptibility (chi(spin)) measurement suggest that the former salt is a Mott-insulator with an exactly half-filled band. Although kappa-(ET)(2)Cu-2(CN)(3) shows only the ESR signal of ET cation radicals, the kappa'-salt shows an additional ESR signal of Cu2+ below about 20 K. The content of Cu2+ is 88-1200 ppm of total copper atoms. It is found that the metallic state and the superconductivity at AP of kappa'-(ET)(2)Cu-2(CN)(3) is realized by a band-filling control by substituting Cu+ with Cu2+.