Revision 1

Superseded · first revision · record

Title: Does the charge order in CsV3Sb5 break time-reversal symmetry
Plain: Some experiments suggest that the charge order in CsV3Sb5 comes with tiny circulating electric currents (loop currents) that break time-reversal symmetry, while sensitive optical tests see nothing.
Precise: Determine whether the $2x2$ charge-density-wave state of CsV3Sb5 ($T_{\mathrm{CDW}} = 94\,\mathrm{K}$) breaks time-reversal symmetry, as in loop-current (chiral flux) phases. Reconcile muSR and field-trained transport and optical signals with high-resolution polar Kerr data and spin-polarized STM that found no signal. An answer is a symmetry-resolved measurement on the same crystals with sensitivity sufficient to detect the orbital moments predicted by loop-current theory.
Settled by: Kerr, muSR and neutron or NMR measurements on the same crystals, with a calibrated sensitivity below the predicted loop-current moment.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: contested
Status note: High-resolution polar Kerr studies (2022, 2025) found no signal, while muSR and some optical and transport data report time-reversal breaking.
Posed since: 2021