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

Ni Z, Wang K, Zhang Y, Pozo O, Xu B, Han X, Manna K, Paglione J, Felser C, Grushin AG, De Juan F, Mele EJ, Wu L (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Nature Communications Nature Publishing Group: Nature Communications

Book Volume: 12

Article Number: 154

Journal Issue: 1

DOI: 10.1038/s41467-020-20408-5

Abstract

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.

Involved external institutions

University of Grenoble Alpes (UGA) / Université de Grenoble FR France (FR) Donostia International Physics Center (DIPC) ES Spain (ES) University of Pennsylvania US United States (USA) (US) University of Maryland US United States (USA) (US) Massachusetts Institute of Technology (MIT) US United States (USA) (US) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) ES Spain (ES) Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids DE Germany (DE) University of Fribourg / Universitè de Fribourg CH Switzerland (CH)

How to cite

APA:

Ni, Z., Wang, K., Zhang, Y., Pozo, O., Xu, B., Han, X.,... Wu, L. (2021). Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi. Nature Communications, 12(1). https://doi.org/10.1038/s41467-020-20408-5

MLA:

Ni, Zhuoliang, et al. "Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi." Nature Communications 12.1 (2021).

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