Study on the Kondo effect of ions with multi-electron occupancy

多电子占据离子的近藤效应研究

• 批准号: 09640451
• 负责人: SAKAI Osamu
• 金额: $ 2.24万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640451/
• 关键词: two channel Kondo model; non-Fermi liquid; Uranium compound; magnetic impurity; Anderson model; numerical renormalization group; ラウン化合物

We have studied following subjects.(1) It is known that the impurity Anderson model (TAM), which is a fundamental model for the magnetic ion in metal, has certainly the local Fermi liquid (LFL) properties in large hybridization limit. Does the non-Fermi liquid (NFL) state appear in the LAM? If it does, what kind of transition occurs between the LFL and the NFL states.(2) The system1 U_xTh_<1-x>Ru2Si_2 shows anomalous low temperature behaviors similar to those of the NFL state of the two channel Kondo model (TCKM) type. But its resistivity decreases with decreasing temperature. Usually it is expected to increase in the TCKM.Can this resistivity be explained based on the IAM?(3) It is known that the TCKM has a residual entropy 1/ In at T=0. This will be released under the lowering of the crystal symmetry, and the specific heat will show a peak at a characteristic temperature. How the increase of the magnetic susceptibility with - In T behave near the characteristic temperature?Following conclusions are derived. (1) The IAM has various types of ground states including both LFL and NFL natures depending on the crystalline field when the hybridization is changed. (2) We can expect the decreasing resistivity when the valence fluctuation between f^2 and f^3ates dominates. (3) The characteristic temperature is about 1/10 of the crystalline field splitting. At that temperature the increase of the susceptibility saturates. The residual entropy in the NFL state is still 1/ in 2 even when the parameters are situated very near the transition point to the LFL state.Recently, the specific heat under strong magnetic field is measured for U_xTh_<1-x>Ru_2Si_2, and the residual entropy is not observed. Based on the results of the present study, we may conclude that the scenario of the TCKM type seems not applicable simply to this system. Roles of the dynamical Jahn-Teller effect are now under consideration.

我们已经研究了以下受试者。（1）众所周知，杂质的Anderson模型（TAM）是金属中磁离子的基本模型，肯定具有较大的杂交极限的局部费米液体（LFL）特性。非Fermi液体（NFL）状态是否出现在LAM中？如果确实如此，LFL和NFL状态之间发生了什么样的过渡。（2）System1 U_XTH_ <1-X> RU2SI_2显示了与两个通道近托模型（TCKM）类型NFL状态相似的异常低温行为。但是它的电阻率随温度降低而降低。通常，预计TCKM中会增加这种电阻率。这将在晶体对称性的降低下释放，并且特定的热将在特征温度下显示峰值。在特征温度附近的磁敏感性增加如何？得出结论之后。 （1）IAM具有各种类型的基态，包括LFL和NFL定义，具体取决于杂交时的结晶场。 （2）当f^2和f^3之间的价波动占主导地位时，我们可以期望电阻率下降。 （3）特征温度约为晶体场分裂的1/10。在该温度下，易感性的增加饱和。即使参数位于LFL状态的过渡点附近，NFL状态中的残留熵仍然为1/ in 2。根据本研究的结果，我们可以得出结论，TCKM类型的场景似乎不适用于该系统。动态Jahn-Teller效应的作用正在考虑。

项目成果

H.-D.Kim, O.Sakai,: "Surface and Bulk 4f-Photoemission Spectra of CeIn_3 and CeSn_3" Phyisical Review. B56・3. 1620-1624 (1997)

H.-D.Kim、O.Sakai：“CeIn_3 和 CeSn_3 的表面和体 4f 光电子发射光谱”B56・3（1997 年）。

Hiroshi Kumigashira, Osamu Sakai,: "Surface and Bulk 4f Electron Structure of CeIn_3 and CeSn_3" Journal of Magnetism and Magnetic Materials. (印刷中). (1998)

Hiroshi Kumigashira、Osamu Sakai，“CeIn_3 和 CeSn_3 的表面和体 4f 电子结构”《磁性与磁性材料杂志》（出版中）。

M.Tsunekawa, O.Sakai,: "High Resolution Photoemision Study of CeRu_2Si_2" Solid State Communications. 103・12. 659-662 (1997)

M.Tsunekawa，O.Sakai，“CeRu_2Si_2 的高分辨率光电发射研究”103・12（1997）。

Ryousuke Shiina: "Interplay of Fileld-Induced Multipoles in CeB_6" Journal of Physical Society of Japan. 67・3. 941-949 (1998)

Ryousuke Shiina：“CeB_6 中场致多极的相互作用”日本物理学会杂志 67・3（1998）。

Ryu Takayama: "Singlc Impurity Anderson Model with Coulomb Repulsion between Conduction Electrons on the Nearest Neighbour Ligand Orbital" Journal of Physical Society of Japan. 67・6. 1844-1847 (1998)

Ryu Takayama：“最近邻配体轨道上传导电子之间的库仑排斥的 Singlelc 杂质安德森模型”日本物理学会杂志 67・6 1844-1847（1998 年）。