Giant density-of-states van Hove singularities in the face-centered cubic lattice

Igoshev, P. A.; Irkhin, V. Yu.

doi:10.1016/j.physleta.2022.128107

Cited by 4 publications

(3 citation statements)

References 33 publications

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“…Previous measurements of the magnetic, transport, and thermodynamic properties strongly support this point [16,17]. Density functional theory (DFT) calculations show flat bands at the Fermi level around the L and W high symmetry points which generate a van Hove singularity responsible for the weak ferromagnetic ordering in the material and play an important role in the metamagnetic transition in a weak magnetic field, Lifshitz transitions, and non-Fermi-liquid behavior [18]. The resulting sensitivity of the predicted Fermi surface to details of the calculation can be seen in the literature, as discussed below.…”

Section: Introductionmentioning

confidence: 84%

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn₂

2022

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The Fermi surface topology plays an important role in the macroscopic properties of metals. It can be particularly sensitive to electron correlation, which appears to be especially significant for the weak itinerant ferromagnet ZrZn2. Here, we look at the differences in the predicted Fermi surface sheets of this metallic compound in its paramagnetic phase for both density functional theory (DFT) and the combination of DFT with dynamical mean field theory (DFT+DMFT). The theoretical spectral functions evaluated at the Fermi level were used along with calculations of the electron-positron momentum density (also known as the two-photon momenutm density) in k-space to provide insights into the origin of certain features of the Fermi surface topology. We compare this two photon momentum density to that extracted from the positron annihilation experimental data (Phys.Rev.Lett.92,107003 (2004)). The DFT+DMFT densities are in better agreement with the experiment than the DFT, particularly with regard to the flat bands around the L and W high symmetry points. The experimental neck around L, which relates to a van Hove singularity, is present in DFT+DMFT but not in the DFT. We find that these flat bands, and as such the Fermi surface topology, are sensitive to the many body electron correlation description, and show that the positron annihilation technique is able to probe this. This description is significant for the observed behavior such as the Lifshiftz transition around the quantum critical point.

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Section: Introductionmentioning

confidence: 84%

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn₂

2022

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“…Although van Hove-boosted Kondo physics may be observable in other systems (including 3d bulk metals [87,88] with magnetic impurities), we note that TBG stands out as a uniquely tunable platform. Furthermore, TBG also allows one to study the complex interplay of these effects with Dirac physics.…”

Section: Discussionmentioning

confidence: 78%

Kondo effect in twisted bilayer graphene

et al. 2023

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The emergence of flat bands in twisted bilayer graphene at the magic angle can be understood in terms of a vanishing Fermi velocity of the Dirac cone. This is associated with van Hove singularities approaching the Fermi energy and becoming higher-order. In the density of states, this is reflected by flanking logarithmic van Hove divergences pinching off the central Dirac cone in energy space. The low-energy pseudogap of the Dirac cone away from the magic angle is replaced by a power-law divergence due to the higher-order van Hove singularity at the magic angle. This plays an important role in the exotic phenomena observed in this material, such as superconductivity and magnetism, by amplifying electronic correlation effects. Here we investigate one such correlation effect-the Kondo effect due to a magnetic impurity embedded in twisted bilayer graphene. We use the Bistritzer-MacDonald model to extract the low-energy density of states of the material as a function of twist angle and study the resulting quantum impurity physics using perturbative and numerical renormalization group methods. Although at zero temperature the impurity is only Kondo screened precisely at the magic angle, we find highly nontrivial behavior at finite temperatures relevant to experiments, due to the complex interplay between Dirac, van Hove, and Kondo physics.

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“…Realization of VHS in more general and applicable 3D systems is desired [24][25][26][27][28] but rarely reported. Here, we propose to realize 3D VHS utilizing the magnetic Weyl semimetal.…”

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confidence: 99%

The discovery of three-dimensional Van Hove singularity

Wu,

Shi,

Ozerov

et al. 2024

Nat Commun

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Arising from the extreme/saddle point in electronic bands, Van Hove singularity (VHS) manifests divergent density of states (DOS) and induces various new states of matter such as unconventional superconductivity. VHS is believed to exist in one and two dimensions, but rarely found in three dimension (3D). Here, we report the discovery of 3D VHS in a topological magnet EuCd2As2 by magneto-infrared spectroscopy. External magnetic fields effectively control the exchange interaction in EuCd2As2, and shift 3D Weyl bands continuously, leading to the modification of Fermi velocity and energy dispersion. Above the critical field, the 3D VHS forms and is evidenced by the abrupt emergence of inter-band transitions, which can be quantitatively described by the minimal model of Weyl semimetals. Three additional optical transitions are further predicted theoretically and verified in magneto-near-infrared spectra. Our results pave the way to exploring VHS in 3D systems and uncovering the coordination between electronic correlation and the topological phase.

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Giant density-of-states van Hove singularities in the face-centered cubic lattice

Cited by 4 publications

References 33 publications

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn₂

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn₂

Kondo effect in twisted bilayer graphene

The discovery of three-dimensional Van Hove singularity

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Giant density-of-states van Hove singularities in the face-centered cubic lattice

Cited by 4 publications

References 33 publications

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn2

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn2

Kondo effect in twisted bilayer graphene

The discovery of three-dimensional Van Hove singularity

Contact Info

Product

Resources

About

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn₂

Local electron correlation effects on the fermiology of the weak itinerant ferromagnet ZrZn₂