Year: 2020
Type: article
Abstract: Chiral topological semimetals are materials that break both inversion and mirror symmetries. They host interesting phenomena such as the quantized circular photogalvanic effect (CPGE) and the chiral magnetic effect. In this work, we report a comprehensive theoretical and experimental analysis of the linear and nonlinear optical responses of the chiral topological semimetal RhSi, which is known to host multifold fermions. We show that the characteristic features of the optical conductivity, which display two distinct quasi-linear regimes above and below 0.4 eV, can be linked to excitations of different kinds of multifold fermions. The characteristic features of the CPGE, which displays a sign change at 0.4 eV and a large non-quantized response peak of around 160 μA/V 2 at 0.7 eV, are explained by assuming that the chemical potential crosses a flat hole band at the Brillouin zone center. Our theory predicts that, in order to observe a quantized CPGE in RhSi, it is necessary to increase the chemical potential as well as the quasiparticle lifetime. More broadly, our methodology, especially the development of the broadband terahertz emission spectroscopy, could be widely applied to study photogalvanic effects in noncentrosymmetric materials and in topological insulators in a contact-less way and accelerate the technological development of efficient infrared detectors based on topological semimetals.
Source: npj Quantum Materials
Institutions: University of Pennsylvania, University of Fribourg, Institut polytechnique de Grenoble, Centre National de la Recherche Scientifique, Institut Néel, Max Planck Institute for Chemical Physics of Solids, Massachusetts Institute of Technology, Indian Institute of Technology Delhi, Drexel University, Ikerbasque, Donostia International Physics Center
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,040
Funders: National Science Foundation, U.S. Department of Energy, University of Pennsylvania, European Commission, Agence Nationale de la Recherche, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Materials Research Science and Engineering Center, Harvard University, Division of Materials Research, Army Research Office
Awards: G1051554911, Linear and non linear effects in driven 3D topological materials, G1461678227, G155958390, Materials Research Science and Engineering Center, Grenoble Quantum Engineering Doctoral Programme, G2567800894, PREDICTIVE THEORY OF TOPOLOGICAL STATES OF MATTER, G434337789, Superconductivity, magnetism and unconventional charge dynamics of high temperature superconductors, oxide thin films and heterostructures, G5599649393, G584641232, G5934060963, G6234232976, G628552264, G7147610287
OpenAlex ID: W3031786549