Past colloquia and seminars


Correlated multiorbital physics in low dimensions

Academic or specialist Seminar

Multiorbital systems exhibit a diverse range of fascinating phenomena stemming from the interplay of charge, orbital, and spin degrees of freedom. Notably, the orbital-selective Mott phase (OSMP) stands out as an intriguing effect, where interactions on a multiorbital Fermi surface selectively localize electrons within specific orbitals. Such a scenario is believed to be realized in low-dimensional iron-based superconductors of the 123 family. In this seminar, I will present a comprehensive exploration of correlated multiorbital physics in low dimensions, using density-matrix renormalization group techniques. First, I will discuss the rich magnetism originating in the OSMP in the ladder geometry, including the experimentally observed exotic block magnetism, novel block-spiral states, and the quantum spin-flux phase. Second, I will explore how the emergence of block-spiral magnetism leads to an interaction-induced topological transition. At this transition, spiral spin order, p-wave superconductivity, and Majorana edge states emerge simultaneously. Lastly, I will focus on the electronic properties and reveal the presence of unique Hund bands in the equilibrium spectra of multiorbital models. These bands occur at energies given only by the Hund coupling J_H, as distinct from the Hubbard satellites following the interaction U. Their presence can be observed in the experimentally relevant single-particle and optical spectra.

When? 12.06.2023 17:00
Where? PER 08 2.73
Chemin du Musée 3
1700 Fribourg
speaker Maksymilian Środa,
Wrocław University of Science and Technology (Poland)
Contact Département de physique, groupe Werner
Prof. Philipp Werner