A critical reexamination of the non-reciprocal x-ray gyrotropy in V$_2$O$_3$

Abstract

We critically review the experimental determination of the nonreciprocal x-ray gyrotropy in the monoclinic antiferromagnetic insulating phase of V$_2$O$_3$ highlighting some of its paradoxical consequences. We also note the apparent absence of a normal (non magnetic) linear dichroism in the data and speculate on the possible reasons for it. Given the importance of the implications of a non reciprocal effect for the physics of V$_2$O$_3$, one of the paradigmatic strongly correlated system, we point up the need for at least repeating the experiment under better controlled conditions and suggest possible tests for establishing unambiguously its existence.