Possible Structural Transformation and Enhanced Magnetic Fluctuations in Exfoliated \(\alpha\)-RuCl\(_3\)

We present initial Raman spectroscopy experiments on exfoliated flakes of \(\alpha\)-RuCl\(_3\), from tens of nm thick down to single layers. Besides unexpectedly finding this material to be air stable, in the thinnest layers we observe the appearance with decreasing temperature of a symmetry-forbidden mode in crossed polarization, along with an anomalous broadening of a mode at 164 cm\(^{-1}\) that is known to couple to a continuum of magnetic excitations. This may be due to an enhancement of magnetic fluctuations and evidence for a distorted honeycomb lattice in single- and bi-layer samples.