Is the anisotropy of the upper critical field of Sr${}_2$RuO${}_4$ consistent with a helical $p$-wave state?

JIngchuan Zhang, Christopher Lörscher, Qiang Gu +1

We calculate the angular and temperature $T$ dependencies of the upper critical field $H_{c2}(\theta ,\varphi ,T)$ for the $C_{4v}$ point group helical $p$-wave states, assuming a single uniaxi…