arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2012.04018cond-mat.str-el
收藏

Mott带隙的双交换增强磁蓝移

Double-Exchange Enhanced Magnetic Blue-Shift of Mott Gaps

Mohsen Hafez-Torbati, Davide Bossini, Frithjof B. Anders, Götz S. Uhrig

摘要:

由强关联引起的电荷激发的实质能隙是莫特绝缘体的特征。我们研究了长程反铁磁序对莫特能隙的影响。我们的关键发现是,莫特间隙增加的磁有序:磁蓝移(MBS)发生。因此,在哈伯德模型中,该效应与领先阶中的交换耦合成比例。在具有额外局域自旋的系统中,双交换机制引起对MBS的额外贡献,其与前导阶中的跳跃成比例。自旋和电荷自由度之间的耦合有可能使Mott系统中的自旋到电荷转换在仅由跳跃和交换确定的极端时间尺度上实现,因为该过程中不涉及自旋-轨道介导的角动量转移。鉴于自旋电子和磁振子的应用,观察到几个完整类别的化合物显示出交换和双交换效应是非常有希望的。例如,我们表明,磁贡献的带隙蓝移观察到的光学电导率的$α$ -MnTe被正确地解释为MBS的莫特间隙。

英文摘要:

A substantial energy gap of charge excitations induced by strong correlations is the characteristic feature of Mott insulators. We study how the Mott gap is affected by long-range antiferromagnetic order. Our key finding is that the Mott gap is increased by the magnetic ordering: a magnetic blue-shift (MBS) occurs. Thus, the effect is proportional to the exchange coupling in the leading order in the Hubbard model. In systems with additional localized spins the double-exchange mechanism induces an additional contribution to the MBS which is proportional to the hopping in the leading order. The coupling between spin and charge degrees of freedom bears the potential to enable spin-to-charge conversion in Mott systems on extreme time scales determined by hopping and exchange only, since a spin-orbit mediated transfer of angular momentum is not involved in the process. In view of spintronic and magnonic applications, it is highly promising to observe that several entire classes of compounds show exchange and double-exchange effects. Exemplarily, we show that the magnetic contribution to the band-gap blue-shift observed in the optical conductivity of $α$-MnTe is correctly interpreted as the MBS of a Mott gap.

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。

↑