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arXiv 2408.04022cond-mat.str-el
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热致低自旋到高自旋转变对关联金属输运性质的强烈影响

Strong effects of thermally induced low-spin-to-high-spin crossover on transport properties of correlated metals

Johanna Moser, Jernej Mravlje, Markus Aichhorn

AI总结:

本研究使用动力学平均场理论探讨多轨道金属中热致低自旋到高自旋转变对电子输运的影响,发现高自旋形成导致的散射增强效应超过平行导电通道效应,可使电阻率增加三倍。

摘要:

我们使用动力学平均场理论(dynamical mean-field theory)研究多轨道金属中的电子输运如何受到关联的(名义上)空轨道的影响,这些轨道靠近费米能级。具体而言,我们在Bethe晶格上研究2+1轨道和3+2轨道(即t2g+eg)模型,其晶体场设置使得较高能级的轨道在低温下几乎为空,但在高温下获得不可忽略的占据率。高温区域的特征是载流子的热激发,导致更高的磁响应(即热致低自旋到高自旋转变),并对电阻率产生显著影响,其中可以区分两种相反的效应:一方面由于高自旋形成和散射相空间增加导致的散射增强,另一方面是额外的平行导电通道。前一种效应更强,可以观察到在某些情况下高温下电阻率增加三倍,尽管未占据带的占据率仍然很小(<10%)。我们讨论了这些发现对关联材料输运性质的意义。

英文摘要:

We use dynamical mean-field theory to study how electronic transport in multi-orbital metals is influenced by correlated (nominally) empty orbitals that are in proximity to the Fermi level. Specifically, we study 2 + 1 orbital and 3 + 2 orbital (i.e. t2g + eg ) models on a Bethe lattice with a crystal field that is set so that the higher lying orbitals are nearly empty at low temperatures but get a non-negligible occupancy at elevated temperature. The high temperature regime is characterized by thermal activation of carriers leading to higher magnetic response (i.e., thermally induced low-spin to high-spin transition) and substantial influence on resistivity, where one can distinguish two counteracting effects: increased scattering due to formation of high spin and increased scattering phase space on one hand, and additional parallel conduction channel on the other. The former effect is stronger and one may identify cases where resistivity increases by a factor of three at high temperatures even though the occupancy of the unoccupied band remains small (< 10%). We discuss implications of our findings for transport properties of correlated materials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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