Hole trapping by Ni, Kondo effect and electronic phase diagram in nonsuperconducting Ni-substituted La2-xSrxCu1-yNiyO4
Hole trapping by Ni, Kondo effect and electronic phase diagram in nonsuperconducting Ni-substituted La2-xSrxCu1-yNiyO4
复制标题
非超导 Ni 取代 La2-xSrxCu1-yNiyO4 中 Ni 的空穴捕获、近藤效应和电子相图
DOI：
10.1103/physrevb.82.054519
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发表时间：
2010
影响因子：
3.7
通讯作者：
Isao Watanabe
中科院分区：
文献类型：
--
作者：
Kyoichi Suzuki;Tadashi Adachi;Y. Tanabe;Yoji Koike;T. Kawamata;Risdiana;Takao Suzuki;Isao Watanabe
为了研究高 Tc 铜酸盐在大范围温度和空穴浓度下正常状态下的电子态，在非超导 Ni 取代的 La2-xSrxCu1-yNiyO4 中进行了比热、电阻率、磁化强度和 μ 子自旋弛豫 (muSR) 测量，其中通过用 Ni 部分取代 Cu 来抑制超导性，而不干扰 CuO2 平面中的 Cu 自旋相关性，因此很多。在欠掺杂状态下，我们发现Ni周围同时存在弱局域空穴和高温下的巡回空穴。随着温度的降低，所有空穴趋于局域化，随后在低温下发生可变范围的跳跃传导。最后，在基态下，发现每个Ni2+离子都强烈捕获一个空穴，并出现磁有序态。另一方面，在过掺杂状态下，人们发现在低温下每个 Ni2+ 自旋周围会形成类似 Kondo 的态。总之，非超导La2-xSrxCu1-yNiyO4的基态在空穴掺杂后从具有Ni2+强空穴捕获的磁有序态转变为由于Ni2+自旋而具有类似Kondo行为的金属态，并且由于相分离到短程磁有序区和金属区，量子相变是类似交叉的。
In order to investigate the electronic state in the normal state of high-Tc cuprates in a wide range of temperature and hole-concentration, specific-heat, electrical-resistivity, magnetization and muon-spin-relaxation (muSR) measurements have been performed in non-superconducting Ni-substituted La2-xSrxCu1-yNiyO4 where the superconductivity is suppressed through the partial substitution of Ni for Cu without disturbing the Cu-spin correlation in the CuO2 plane so much. In the underdoped regime, it has been found that there exist both weakly localized holes around Ni and itinerant holes at high temperatures. With decreasing temperature, all holes tend to be localized, followed by the occurrence of variable-range hopping conduction at low temperatures. Finally, in the ground state, it has been found that each Ni2+ ion traps a hole strongly and that a magnetically ordered state appears. In the overdoped regime, on the other hand, it has been found that a Kondo-like state is formed around each Ni2+ spin at low temperatures. In conclusion, the ground state of non-superconducting La2-xSrxCu1-yNiyO4 changes upon hole doping from a magnetically ordered state with the strong hole-trapping by Ni2+ to a metallic state with Kondo-like behavior due to Ni2+ spins, and the quantum phase transition is crossover-like due to the phase separation into short-range magnetically ordered and metallic regions.