Non-Hermitian perspective of the band structure in heavy-fermion systems

By Tsuneya Yoshida, R. Peters, N. Kawakami. Physical review B, 2018

198 citations recorded by the source corpus.

We analyze a two-dimensional Kondo lattice model with special emphasis on non-Hermitian properties of the single-particle spectrum, following a recent proposal by Kozii and Fu. Our analysis based on the dynamical mean-field theory elucidates that the single-particle spectral weight shows the exceptional points (EPs). Correspondingly, the spectral weight exhibits the band touching, resulting in a structure similar to the Fermi arc. Furthermore, we find an intriguing phenomenon arising from the periodicity of the lattice. The EPs generated by two distinct Dirac points merge and change into a hybrid point, which vanishes as the exchange interaction is increased. Accordingly, the paramagnetic phase in the low-temperature region shows a significant difference from noninteracting fermions: the imaginary part of the self-energy yields the Fermi loop without any defective points.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/34699736c0d8321c07697abdfa8458001539ddfb

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Citations in the corpus

Topological photonics (2018, background): “…et al., 2015) as well as “Fermi arc”-type states that connect between exceptional points in two-dimensional systems (Kozii and Fu, 2017; Malzard and Schomerus, 2018a; Zhou et al., 2018); a related phenomenon was examined in the context of heavy-fermion systems (Yoshida, Peters, and Kawakami, 2018).”
Anomalous helical edge states in a non-Hermitian Chern insulator (2018, unknown): “The appearance of such large gapless phases arises from the fact that a level degeneracy requires fine-tuning two parameters for a general 2×2 non-Hermitian matrix, although it requires fine-tuning three parameters for a general 2×2 Hermitian matrix [62, 65, 76, 127]; non-Hermitian systems in two di”
Non-Hermitian systems and topology: A transfer-matrix perspective (2018, background): “[31] Tsuneya Yoshida, Robert Peters, and Norio Kawakami, “Non-Hermitian perspective of the band structure in heavy-fermion systems,” Physical Review B 98, 035141 (2018).”
Perspective on topological states of non-Hermitian lattices (2019, background): “Today, this has shifted to non-Hermitian Hamiltonians regarded as an effective description of, for example, open quantum systems [23, 24], where the finite lifetime introduced by electronelectron or electron-phonon interactions [25, 26], or disorder [27], is modeled through a nonHermitian term, or i”
Symmetry-protected nodal phases in non-Hermitian systems (2018, background): “Very recently, intense theoretical [7–37] and experimental [38–45] efforts have been made to extend the concept of topological band structures to non-Hermitian (NH) systems which play an important role in the effective description of dissipation effects in various physi-”
Exceptional topology of non-Hermitian systems (2019, unknown): “…it has been proposed that dissipation in the form of emergent non-Hermiticity can have a profound impact on the low-energy description of interacting and disordered quantum matter (Kozii and Fu, 2017; Yoshida, Peters, and Kawakami, 2018; Zyuzin and Zyuzin, 2018; Michishita and Peters, 2020).”