The TPSC+ approach: benchmarks and spin fluctuations in the electron-doped cuprates

One of the important models for the study of electron interactions in strongly correlated materials is the Hubbard model. There is a handful of approaches that find solutions to this model that satisfy the Mermin-Wagner theorem in two dimensions. One of these methods is the Two-Particle Self-Consistent approach (TSPC) [1][2], which has given a satisfactory description of the ARPES pseudogap in electron-doped cuprates. However, this method is not valid in regimes where the antiferromagnetic correlation length becomes too large.

Thus, we propose an improvement of the method, called TPSC+ [3]. The main hypothesis of TPSC+ is that the spin and charge susceptibilities are now dependent on the interacting Green’s function. We show comparisons to benchmarks [3][4] for different quantities for the 2D Hubbard model and discuss the different regions of the phase diagram.



[1] Vilk, Y. M., et al. Journal de Physique I 7, n^o 11 (novembre 1997): 1309-68.

[2] K. Zantout., et al. Annalen Der Physik 533, n^o 2 (2021): 2000399.

[3] Schäfer, Thomas, et al. Physical Review X 11, n^o 1 (23 mars 2021): 011058.

[4] Šimkovic IV, arXiv, 12 octobre 2021. 2110.05863.