Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
Institut für Theoretische Physik III, Ruhr-Universität Bochum, 44801 Bochum, Germany.
Nat Commun. 2017 Feb 8;8:14317. doi: 10.1038/ncomms14317.
The combination of electronic correlations and Fermi surfaces with multiple nesting vectors can lead to the appearance of complex multi-Q magnetic ground states, hosting unusual states such as chiral density waves and quantum Hall insulators. Distinguishing single-Q and multi-Q magnetic phases is however a notoriously difficult experimental problem. Here we propose theoretically that the local density of states (LDOS) near a magnetic impurity, whose orientation may be controlled by an external magnetic field, can be used to map out the detailed magnetic configuration of an itinerant system and distinguish unambiguously between single-Q and multi-Q phases. We demonstrate this concept by computing and contrasting the LDOS near a magnetic impurity embedded in three different magnetic ground states relevant to iron-based superconductors-one single-Q and two double-Q phases. Our results open a promising avenue to investigate the complex magnetic configurations in itinerant systems via standard scanning tunnelling spectroscopy, without requiring spin-resolved capability.
电子相关和费米面与多个嵌套向量的组合可能导致复杂的多 Q 磁基态的出现，承载不寻常的状态，如手性密度波和量子霍尔绝缘体。然而，区分单 Q 和多 Q 磁相是一个众所周知的实验难题。在这里，我们从理论上提出，在磁性杂质附近的局域态密度（LDOS），其取向可以通过外部磁场控制，可用于描绘出巡游系统的详细磁构型，并明确区分单 Q 和多 Q 相。我们通过计算并对比嵌入在三种不同与铁基超导体相关的磁性基态中的磁性杂质附近的 LDOS 来证明这一概念，其中一个是单 Q 相，两个是双 Q 相。我们的结果为通过标准扫描隧道光谱学研究巡游系统中的复杂磁构型开辟了一条有希望的途径，而无需自旋分辨能力。
