Nearly Traceless1fNoise in Bismuth

The conductivity fluctuations giving $\frac{1}{f}$ noise in bismuth were found to be extremely nonscalar, with local instantaneous anisotropy in between that of dyads and of traceless tensors. This result requires a symmetry-breaking noise-generating mechanism. Temperature dependence and detailed spectral data show that the $\frac{1}{f}$ kinetics are thermally activated and that the net noise magnitude in thick films is a decreasing function of temperature. A crude model accounting for these results is presented.