Excellent
fits were obtained by Talantsev (MPLB 33, 1950195, 2019) to the temperature (T)-dependent upper critical field
(Hc2(T)) data of H3S reported
by Mozaffari et al. [Nature
Communications 10, 2522 (2019)]by employing four alternative phenomenological models,
each of which invoked two or more properties from its sample-specific set S1 = {Tc, gap, coherence length, penetration depth, jump in sp.ht.}
and a single value of the effective mass (m*) of an electron. Based on the
premise that the variation of Hc2(T) is due to the variation of the chemical potential μ(T), we report here fits to the
same data by employing a T-, μ- and m*-dependent equation for Hc2(T) and three models of μ(T), viz. the linear, the parabolic
and the concave-upward model. For temperatures up to which the data are available,
each of these provides a good fit. However, for lower values of T, their
predictions differ. Notably, the predicted values of Hc2(0) are much higher than in any of the models dealt with by Talantsev.
In sum, we show here that the addressed data are explicable in a framework comprising
the set S2 = {μ, m*, interaction parameterλm, Landau index NL}, which is altogether different from S1.
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