Kavli Affiliate: Cheng Peng
| First 5 Authors: Chaebin Kim, Sumedh Rathi, Naipeng Zhang, Arnab Seth, Nikolai V. Simonov
| Summary:
Disorder significantly impacts the electronic properties of conducting
quantum materials by inducing electron localization and thus altering the local
density of states and electric transport. In insulating quantum magnetic
materials the effects of disorder are less understood and can drastically
impact fluctuating spin states like quantum spin liquids. In the absence of
transport tools, disorder is typically characterized using chemical methods or
by semi-classical modeling of spin dynamics. This requires high magnetic fields
that may not always be accessible. Here, we show that magnetization plateaus —
incompressible states found in many quantum magnets — provide an exquisite
platform to uncover otherwise undetectable amounts of disorder, regardless of
the origin of the plateau. Using optical magneto-spectroscopy on the
Ising-Heisenberg triangular-lattice antiferromagnet K$_2$Co(SeO$_3$)$_2$
exhibiting a 1/3 magnetization plateau, we identify sharp spectroscopic lines,
the fine structure of which serves as a hallmark signature of disorder. Through
analytical and numerical modeling, we show that these fingerprints not only
enable us to quantify minute amounts of disorder but also reveal its nature —
as dilute vacancies. Remarkably, this model explains all details of the
thermomagnetic response of our system, including the existence of multiple
plateaus. Our findings provide a new approach to identifying disorder in
quantum magnets.
| Search Query: ArXiv Query: search_query=au:”Cheng Peng”&id_list=&start=0&max_results=3