Anomalous Spin‐Optical Helical Effect in Ti‐Based Kagome Metal
Abstract
ABSTRACT The kagome lattice stands as a rich platform for hosting a wide array of correlated quantum phenomena, ranging from charge density waves and superconductivity to electron nematicity and loop current states. Direct detection of loop currents in kagome systems has remained a formidable challenge due to their intricate spatial arrangements and the weak magnetic field signatures they produce, and this has made their identification experimentally subtle. This has left their existence and underlying mechanisms a topic of intense debate. In this work, we uncover signatures compatible with loop currents: spin handedness‐selective signals that surpass conventional dichroic, spin, and spin‐dichroic responses. We observe this phenomenon in the kagome metal and we call it the anomalous spin‐optical helical effect. This effect arises from the coupling of light's helicity with spin‐orbital electron correlations, thereby providing an indirect yet sensitive approach to probe loop‐current–related electronic correlations in quantum materials. Our discovery not only enriches the debate surrounding loop currents but also offers new experimental strategies to exploit the electronic phases of quantum materials via light–matter interaction.
Article Details
Authors (35)
Federico Mazzola
Wojciech Brzezicki
Institute of Theoretical Physics Jagiellonian University Kraków Poland
Chiara Bigi
Armando Consiglio
Luciano Jacopo D'Onofrio
CNR‐SPIN c/o Universitá di Salerno Fisciano (SA) Italy
Maria Teresa Mercaldo
Dipartimento di Fisica “E. R. Caianiello” Università di Salerno Fisciano (SA) Italy
Adam Kłosiński
Institute of Theoretical Physics, Faculty of Physics University of Warsaw Warsaw Poland
Francois Bertran
Patrick Le Fèvre
Oliver J. Clark
Mark T. Edmonds
School of Physics and Astronomy Monash University Clayton Australia
Manuel Tuniz
Dipartimento di Fisica Universita degli studi di Trieste Trieste Italy
Alessandro De Vita
Vincent Polewczyk
Jeppe B. Jacobsen
Nanoscience Center, Niels Bohr Institute University of Copenhagen Copenhagen Denmark
Henrik Jacobsen
European Spallation Source ERIC ‐ Data Management and Software Center Lyngby Denmark
Jill A. Miwa
Justin W. Wells
Anupam Jana
Ivana Vobornik
Jun Fujii
Niccolo Mignani
Dipartimento di Fisica Politecnico di Milano Milano Italy
Narges Tarakameh Samani
Dipartimento di Fisica Politecnico di Milano Milano Italy
Alberto Crepaldi
Dipartimento di Fisica Politecnico di Milano Milano Italy
Giorgio Sangiovanni
Anshu Kataria
Dipartimento di Scienze Matematiche, Fisiche e Informatiche Universitá di Parma Parma Italy
Tommaso Morresi
European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) Fondazione Bruno Kessler Trento Italy
Samuele Sanna
Pietro Bonfá
Dipartimento di Scienze Matematiche, Fisiche e Informatiche Universitá di Parma Parma Italy
Brenden R. Ortiz
Materials Science and Technology Division
Ganesh Pokharel
Stephen D. Wilson
Domenico Di Sante
Carmine Ortix
Mario Cuoco