Interactions Remove the Quantization of the Chiral Photocurrent at Weyl Points

Avdoshkin, Alexander; Kozii, Vladyslav; Moore, Joel E.

doi:10.1103/physrevlett.124.196603

Cited by 75 publications

(41 citation statements)

References 53 publications

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“…As discussed below, this peak originates from the double Weyl fermion at the R point, and it is enabled by an accidental window of vanishing CPGE contribution from the Γ point. Finally, we note that electronelectron interactions can also correct the quantized value, as occurs for chiral Weyl semimetals 39 . While it is currently unknown how relevant these corrections are for multifold fermions, the large hole and electron pockets at Γ and R in CoSi suggest that screening should be strong and therefore interactions should have a small effect.…”

Section: Resultsmentioning

confidence: 58%

Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi

et al. 2021

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The absence of mirror symmetry, or chirality, is behind striking natural phenomena found in systems as diverse as DNA and crystalline solids. A remarkable example occurs when chiral semimetals with topologically protected band degeneracies are illuminated with circularly polarized light. Under the right conditions, the part of the generated photocurrent that switches sign upon reversal of the light’s polarization, known as the circular photo-galvanic effect, is predicted to depend only on fundamental constants. The conditions to observe quantization are non-universal, and depend on material parameters and the incident frequency. In this work, we perform terahertz emission spectroscopy with tunable photon energy from 0.2 –1.1 eV in the chiral topological semimetal CoSi. We identify a large longitudinal photocurrent peaked at 0.4 eV reaching ~550 μ A/V2, which is much larger than the photocurrent in any chiral crystal reported in the literature. Using first-principles calculations we establish that the peak originates only from topological band crossings, reaching 3.3 ± 0.3 in units of the quantization constant. Our calculations indicate that the quantized circular photo-galvanic effect is within reach in CoSi upon doping and increase of the hot-carrier lifetime. The large photo-conductivity suggests that topological semimetals could potentially be used as novel mid-infrared detectors.

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Section: Resultsmentioning

confidence: 58%

Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi

et al. 2021

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“…Therefore, in order for the nodes to be exactly two, they need to be located along one of the three axes. Moreover, the requirement that ε ± (k) vanish linearly at p ± F , combined with the fact that a, b, c, d are all even functions of k 3 , implies that the Weyl nodes are located along the third axis: 10) where…”

Section: A Class Of Non-interacting Models For Weyl Semimetalsmentioning

confidence: 99%

“…operator, equal to the identity if q i = (0, 0, 0, 0), and dimensionally equivalent to the composition of a derivative of order q 0 i in direction 0, of a derivative of order q 1 i in direction 1, etc, otherwise 10 (if h = 0, the only non-vanishing contribution to the right side of (3.47) is the one with q i = (0, 0, 0, 0), for all i = 1, . .…”

Section: 31mentioning

confidence: 99%

“…The renormalization operator is defined as R := 1 − L. Notice that RL = LR = 0. 10 In Fourier space, the Fourier symbol of∂ q is a function of k behaving like k…”

Section: 31mentioning

confidence: 99%

“…However, the AB argument cannot be applied to Weyl semimetals: the analysis in [3] requires cancellations between classes of Feynman graphs based on Lorentz and chiral symmetries, which are broken explicitly in any lattice model of interacting electrons. Strangely enough, the issue of universality has not been addressed theoretically until now, despite the huge literature on the effects of interactions 1 [10,20,35,36,49,51,70]. In this paper, we consider a paradigmatic class of lattice models for 3D Weyl semimetals with short-range interactions, generalizing a widely used 'standard' model for these materials, see [9].…”

Section: Introductionmentioning

confidence: 99%

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Anomaly Non-renormalization in Interacting Weyl Semimetals

Giuliani

Mastropietro

Porta

2021

Commun. Math. Phys.

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Weyl semimetals are 3D condensed matter systems characterized by a degenerate Fermi surface, consisting of a pair of ‘Weyl nodes’. Correspondingly, in the infrared limit, these systems behave effectively as Weyl fermions in $$3+1$$ 3 + 1 dimensions. We consider a class of interacting 3D lattice models for Weyl semimetals and prove that the quadratic response of the quasi-particle flow between the Weyl nodes is universal, that is, independent of the interaction strength and form. Universality is the counterpart of the Adler–Bardeen non-renormalization property of the chiral anomaly for the infrared emergent description, which is proved here in the presence of a lattice and at a non-perturbative level. Our proof relies on constructive bounds for the Euclidean ground state correlations combined with lattice Ward Identities, and it is valid arbitrarily close to the critical point where the Weyl points merge and the relativistic description breaks down.

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Floquet Transmission in Weyl/Multi‐Weyl and Nodal‐Line Semimetals through a Time‐Periodic Potential Well

2023

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A quantum pumping protocol through which the quasiparticles of Weyl/multi-Weyl and nodal-line semimetals are subjected to a time-periodic rectangular potential well is considered. The presence of an oscillating potential of frequency 𝝎 creates equispaced Floquet side-bands with spacing ℏ𝝎. As a result, a Fano resonance is observed when the difference in the Fermi energy (i.e., the energy of the incident quasiparticle), and the energy of one of the (quasi)bound state levels of the well, coincides with the energy of an integer number of photons (each carrying energy quantum ℏ𝝎). Using the Floquet theory and the scattering matrix approach in the zero-temperature non-adiabatic pumping limit, characteristic Fano resonance patterns are found in the transmission coefficients. The inflection points in the pumped shot noise spectra also serve as a proxy for the corresponding Fano resonances. Therefore, the pumped shot noise is also numerically evaluated. Finally, the existence of the Fano resonance points is correlated to the (quasi)bound states of the well, by explicitly calculating the bound states of the static well (which are a subset of the bound states of the driven system). Since semimetals with anisotropic dispersions are considered, all the features observed depend on the orientation of the potential well.

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Interactions Remove the Quantization of the Chiral Photocurrent at Weyl Points

Cited by 75 publications

References 53 publications

Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi

Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi

Anomaly Non-renormalization in Interacting Weyl Semimetals

Floquet Transmission in Weyl/Multi‐Weyl and Nodal‐Line Semimetals through a Time‐Periodic Potential Well

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