Determination of the Fermi surface by charge density correlations

The Fermi surface topology plays a crucial role in the study of high-temperature superconductivity cuprates. conventional method for determining is maximum spectral intensity method, which involves numerical analytical continuation Matsubara data one-body Green's function. However, sensitive to noise or precision data, and hence not always reliable. With this mind, we propose simple specific notion as reference surface. It derivative momentum distribution function ${n}_{\mathbit{k}}$ with respect chemical potential $\ensuremath{\mu}$. Our analysis noninteracting system shows that momentum, at $d{n}_{\mathbit{k}}/d\ensuremath{\mu}$ takes value, constitutes surface, coincides relationship between general cases also analyzed. In order numerically demonstrate relationship, calculate compare on two-dimensional Hubbard model within HGW method. results show that, least weak intermediate coupling regimes, using determine We further studied parameters standing realistic materials, found determined by exhibits topological transition charge filling, similar believe reasonable, efficient, potentially valuable approach.