Correlated Quantum Materials (CQM)

Emergent quantum phenomena in van der Waals materials
Van der Waals heterostructures provide an outstanding platform to engineer elusive quantum phenomena, by exploiting materials engineering, twist engineering and proximity effects. We are interested in developing new theoretical routes to exploit the flexibility of these materials to create exotic physics not accessible in conventional compounds. On the theory side, among others, in this line, we recently showed how to generate artificial gauge fields, tunable frustrated magnets, and controllable correlated states in twisted graphene multilayers. In collaboration with experimental groups, we recently showed how to probe magnetic excitations in van der Waals magnets, how to drive van der Waals magnets to a frustrated regime by spin-orbit engineering, and how to probe crystal field effects in twisted graphene multilayers.

Interacting & quasiperiodic topology and exotic excitations in condensed matter systems
The interplay of strong electronic interactions and topology represents one of the most exciting lines in condensed matter, opening venues to engineer quantum excitations not present in nature, such as fractionalized excitations, supersymmetric excitations and emergent topological states. Among others, in this line, we recently showed how to create Chern insulators by exploiting interactions in topological metals, how to engineer topological excitations by exploiting quasiperiodic many-body states, how to create solitonic excitations between quantum disordered magnets and superconductors, and in collaboration with an experimental group how to generate and probe critical quasiperiodic states. 

Engineering and detecting unconventional superconductivity
Unconventional superconductors are highly pursued for their exotic quantum properties, and ultimately for their potential for topological quantum computing. However, these states are extremely rare to find and detect in nature, with very few compounds showing signatures of such physics. Among others, in this line, we recently showed how to create a topological superconductor with antiferromagnets, how to detect the interplay between atomic defects and moire superconductivity in twisted graphene bilayers, how to detect non-unitary multiorbital superconductors in angle-resolved photo-emission spectroscopy experiments, and how to probe the non-uniform superfluid density in superconducting twisted graphene trilayers.

Method development for topological and correlated quantum materials
Understanding exotic phenomena in quantum systems often requires developing new theoretical methods for model analysis and prediction. In particular, we are especially interested in developing new methodologies to understand and detect topological phenomena, and emergent quantum excitations in many-body systems. In this direction, recently we demonstrated how to use machine learning methods to detect topological matter with local measurements, how to disentangle magnetic anisotropy mechanisms from first principles methods, how to compute dynamical topological excitations in many-body systems using kernel polynomial tensor-network methods, and how to probe and quantify intervalley scattering in atomistic models of graphene multilayers. Most of the methods we develop are implemented in freely available open source libraries we have developed to solve quantum many-body problems with tensor networks and study electronic, interacting and topological properties of tight binding models, 

From left to right: Guangze Chen, Timo Hyart, Jose Lado, Timo Kist, Maryam Khosravian, Senna Luntama