where $B=\omega/l$ is the center of the spin peaks. Equation (\[Ts\]) gives the maximum temperature to observe the spin splitting in the MO. Given that $B=\omega/l=\mu^{2}/l\alpha^{2}$, then $T_{s}$ is proportional to $\mu^{2}$, so high Fermi energy favors the observation of the spin splitting in the magnetization. It should be noted that the condition given by equation (\[Ts\]) has to be taken into account alongside with the need of high $\mu$ (about $\mu\gtrsim100$ meV, see figure \[fig1\]) to observe the spin splitting at zero temperature. Therefore, for practical terms, equation (\[Ts\]) should only be applied when $\mu\gtrsim100$ meV.

![\[fig6\]Spin temperature $T_s$, given by equation (\[Ts\]), as a function of the magnetic field $B$ (solid line) and for $\mu=250$ meV (scatter), where $B=\omega/l=\mu^2/l\alpha^2$ at the center of the spin peaks corresponding to the LL $l$.](fig6.eps)

In figure \[fig6\] it is shown the plot of equation (\[Ts\]) as a function of the magnetic field $B$ (solid line) and for $\mu=250$ meV (scatter), where $B=\omega/l=\mu^2/l\alpha^2$. We see that, in general, $T_{s}$ is very low unless $B$ is very high. For instance, at $\mu=250$ meV, we have that $B\sim1$ T gives $T_{s}\sim0.3$ K. Thus, even for high magnetic field, it requires a very low temperature 