The one-dimensional Hubbard model in a magnetic field: Density profiles and ground-state phase diagram

We study the single-band one-dimensional Hubbard model in an arbitrary magnetic field using the cu-mulant Green's functions method (CGFM) with clusters containing 5, 6, 7, and 8 sites. We calculate the occupation numbers as functions of the chemical potential in a positive magnetic field and identify a partially filled region with negative magnetization. We obtain the ground-state phase diagram in chem-ical potential vs. magnetic field coordinates. We include a straightforward application of the CGFM by using a cluster as a correlated quantum dot connected to correlated leads to construct a single-electron transistor that presents a spin-polarised conductance.(c) 2023 Elsevier B.V. All rights reserved.