Anomalous spin-optical helical effect in Ti-based kagome metal
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. This has left their existence and underlying mechanisms a topic of intense debate. In this work, we uncover a hallmark reconcilable with loop currents: spin handedness-selective signals that surpass conventional dichroic, spin, and spin-dichroic responses. We observe this phenomenon in the kagome metal CsTiBi 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, providing a groundbreaking method to visualize loop currents in quantum materials. Our discovery not only enriches the debate surrounding loop currents but also paves the way for new strategies to exploit the electronic phases of quantum materials via light-matter interaction.
Keywords
Cite
@article{arxiv.2502.19589,
title = {Anomalous spin-optical helical effect in Ti-based kagome metal},
author = {Federico Mazzola and Wojciech Brzezicki and Chiara Bigi and Armando Consiglio and Luciano Jacopo D' Onofrio and Maria Teresa Mercaldo and Adam Kłosiński and François Bertran and Patrick Le Fèvre and Oliver J. Clark and Mark T. Edmonds and Manuel Tuniz and Alessandro De Vita and Vincent Polewczyk and Jeppe B. Jacobsen and Henrik Jacobsen and Jill A. Miwa and Justin W. Wells and Anupam Jana and Ivana Vobornik and Jun Fujii and Niccolò Mignani and Narges Samani Tarakameh and Alberto Crepaldi and Giorgio Sangiovanni and Anshu Kataria and Tommaso Morresi and Samuele Sanna and Pietro Bonfá and Brenden R. Ortiz and Ganesh Pokharel and Stephen D. Wilson and Domenico Di Sante and Carmine Ortix and Mario Cuoco},
journal= {arXiv preprint arXiv:2502.19589},
year = {2025}
}