| Weak localization provides a valuable tool for the measurement of basic electronic transport properties in solids. The effects of spin-orbit and magnetic scattering on weak localization have been extensively studied, but the influence of the Zeeman interaction between the conducting electrons and an applied magnetic field has not been fully explored in experiments. We have studied the low temperature magnetoresistance of quench-condensed lithium films with the goal of testing weak localization theory when the spin Zeeman interaction is important.;We have found that electron transport in our films is quasi-ballistic: the electrons' mean free path is greater than the thickness of the film. This is in contrast to the more usual diffusive transport in quench-condensed films of heavier metals. We are able to determine the thickness, the in-plane diffusion constant, and a range of possible values for the mean free path from the weak localization magnetoresistance.;When the spin effects are negligible or the spin-orbit scattering rate high (due to the addition of high-Z impurities), we are able to give an excellent description of the data. However, when the anticipated signature of the spin Zeeman interaction is observed, good fits of the theory to the data can only be obtained with an anomalously large value for the electrons' g-factor. We show how polarization of the magnetic impurities can affect the conducting electrons' precession rate, and we derive an expression for the resulting enhancement of the g-factor. This gives a possible explanation of the data, and it suggests a number of new experiments. |
