155 citations · 992 across the 20 of their papers we have counts for
20 papers
Massless multifold Hopf semimetals
Ansgar Graf, Frédéric Piéchon
Three-dimensional topological semimetals exhibit linear energy band crossing points that act as monopoles of Berry curvature. Here, an alternative class of semimetals is introduced…
Designing flat-band tight-binding models with tunable multifold band touching points
Ansgar Graf, Frédéric Piéchon
Being dispersionless, flat bands on periodic lattices are solely characterized by their macroscopically degenerate eigenstates: compact localized states (CLSs) in real space and Bl…
Berry Curvature and Quantum Metric in -band systems -- an Eigenprojector Approach
Ansgar Graf, Frédéric Piéchon
The eigenvalues of a parameter-dependent Hamiltonian matrix form a band structure in parameter space. In such -band systems, the quantum geometric tensor (QGT), consisting of th…
Dirac points emerging from flat bands in Lieb-kagomé lattices
Lih-King Lim, Jean-Noël Fuchs, Frédéric Piéchon +1
The energy spectra for the tight-binding models on the Lieb and kagomé lattices both exhibit a flat band. We present a model which continuously interpolates between these two limit…
Critical eigenstates and their properties in one and two dimensional quasicrystals
Nicolas Macé, Anuradha Jagannathan, Pavel Kalugin +2
We present exact solutions for some eigenstates of hopping models on one and two dimensional quasiperiodic tilings and show that they are "critical" states, by explicitly computing…
Gap structure of 1D cut and project Hamiltonians
Nicolas Macé, Anuradha Jagannathan, Frédéric Piéchon
We study the gap properties of nearest neighbors tight binding models on quasiperiodic chains. We argue that two kind of gaps should be distinguished: stable and transient. We show…