Experimental Determination of the g Factor in Metallic Zn

The de Haas-van Alphen (dHvA) oscillations associated with the 3rd-zone electron pockets ("needles") in Zn are split into resolved spin subpeaks when detected with the ac-modulation technique at T≤4^∘K. At P~1 bar, ΔₛF is 0.36, where ΔₛF is defined as the |Δ(1/H)| between neighboring subpeaks times the needle dHvA frequency F. The three needle $|g|$ values consistent with ΔₛF=0.36 are 96, 170, and 362, in reasonable agreement with the values 90, 180, and 360 determined by Stark. The parameter ΔₛF decreases with increasing pressure (decreasing c/a ratio) at a rate given by dlnΔₛFdP-0.16 kbar^-1. At higher temperatures, the resolved spin splitting disappears and the apparent phase of the oscillations increases with increasing temperature (increasing c/a). The increase of the phase results from the dominant contribution of one spin state to the needle oscillations at higher temperatures coupled with the increase of ΔₛF with increasing c/a. The tendency of one spin-state contribution to dominate with increasing temperature is due to a difference between the effective masses associated with the 2 spin halves of a needle Landau level. The effective-mass difference is estimated by introducing arguments which depend heavily upon the conclusion, drawn from the experimental pressure dependence of the needle area and m*, that the needles are very free-electron-like. When the Lifshitz and Kosevich expression for the oscillatory susceptibility is modified to include the difference in effective mass, the three $|g|$ values lead to different predictions for the temperature dependence of the phase of the needle oscillations. The value $|g|=170$ is selected, since it alone leads to an increase of the phase with temperature.