Unveiling the hidden nematicity and spin subsystem in FeSe

Abstract

Iron-based superconductors: Hidden nematic and magnetic fluctuations in iron selenide Ultrafast spectroscopy unveils hidden nematic fluctuations and a spin subsystem in the iron-based superconductor iron selenide. Layered iron-based materials recently emerged as a new class of high temperature superconductor. The mechanism of superconductivity in these materials, however, is a contentious issue. Nematic ordering is thought to be a key ingredient, but the apparent absence of magnetic ordering in iron selenide, which is the iron-based superconductor with the simplest structure, has caused confusion over what drives the nematicity. An international team of researchers led by Chih-Wei Luo and Jenh-Yih Juang from National Chiao Tung University use polarized ultrafast spectroscopy to unveil a hidden spin subsystem in FeSe, along with both nematic and magnetic fluctuations at relatively high temperatures, providing insights into the driving factors of nematicity in this fascinating material.