Ferromagnetic Instability and Finite-Temperature Properties of Two-Dimensional Electron Systems with van Hove Singularities

Andrey A. Katanin, Hiroyuki Yamase, Valentin Yu. Irkhin
2011 Journal of the Physical Society of Japan  
We study a ferromagnetic tendency in the two-dimensional Hubbard model near van Hove filling by using a functional renormalization-group method. We compute temperature dependences of magnetic susceptibilities including incommensurate magnetism. The ferromagnetic tendency is found to occur in a dome-shaped region around van Hove filling with an asymmetric property: incommensurate magnetism is favored near the edge of the dome above van Hove filling whereas a first-order-like transition to the
more » ... romagnetic ground state is expected below van Hove filling. The dome-shaped phase diagram is well captured in the Stoner theory by invoking a smaller Coulomb interaction. Triplet p-wave superconductivity tends to develop at low temperatures inside the dome and extends more than the ferromagnetic region above van Hove filling.
doi:10.1143/jpsj.80.063702 fatcat:pmfacsy24fdrfd43bgcscoa2su