Abstract
We study the occurrence and the origin of ferromagnetic fluctuations in the longitudinal spin susceptibility of the $t$-$t'$-Rashba-Hubbard model on the square lattice. The combined effect of the second-neighbor hopping $t'$ and the spin-orbit coupling leads to ferromagnetic fluctuations in a broad filling region. The spin-orbit coupling splits the energy bands, leading to two van Hove fillings, where the sheets of the Fermi surface change their topology. Between these two van Hove fillings the model shows ferromagnetic fluctuations. We find that these ferromagnetic fluctuations originate from interband contributions to the spin susceptibility. These interband contributions only arise if there is one holelike and one electronlike Fermi surface, which is the case for fillings in between the two van Hove fillings. We discuss implications for experimental systems and propose a test on how to identify these types of ferromagnetic fluctuations in experiments.
Highlights
Recent technological advances in atomic-scale synthesis have allowed several experimental groups to fabricate heterostructure interfaces with tailored electronic structures and symmetry properties [1]
We have found that for fillings in between these two Van Hove singularities, there exist dominant ferromagnetic fluctuations in the longitudinal susceptibility
The ferromagnetic fluctuations remain largely unchanged by on-site interactions U of small and intermediate strength
Summary
Recent technological advances in atomic-scale synthesis have allowed several experimental groups to fabricate heterostructure interfaces with tailored electronic structures and symmetry properties [1]. In order to understand how interface ferromagnetism can emerge in these heterostructures, it is necessary to study the interplay of inversion-symmetry breaking, spin-orbit coupling, and correlation effects Motivated by these deliberations, we study in this paper itinerant magnetic fluctuations in the Rashba-Hubbard model on the square lattice, which describes the salient features of interface electrons in a great number of heterostructures [17,18,19,20,21] and which, is relevant for many non-. It follows from this insight that longitudinal FM fluctuations occur quite commonly, i.e., in any Rashba system with one holelike and one electronlike Fermi surface This is confirmed by our numerical calculations, which show that FM fluctuations are present whenever the filling is in between nvH2 and nvH1 , independent of the magnitude of the second-neighbor hopping and SOC. In Appendixes A and B we provide the main mathematical aspects of the present calculation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
