The wide family of 2D materials (2DMs) includes metals, semiconductors, superconductors, dielectrics, ferroics and more, each displaying novel phenomena due to the qualitatively different nature of interactions in 2D. However, the real delight is in the ability to combine different 2D materials into atomically defined heterostructures by simply stacking layers, engineering interactions between...
Interplay of superconductivity and density wave orders has been at the forefront of research of correlated electronic phases for a long time. The balance between these two competing orders can be tuned by means of lattice deformation, i.e. pressure or strain. 2H-NbSe$_2$ is considered to be an ideal system for studying this interplay, but the origin of charge density wave in this material is...
One of the limitations in exploiting the spin injection and transport properties of graphene is its strong electronic interaction with magnetic contacts. The π-states form complex and non-linear hybrid states when graphene is interfaced with 3d magnetic materials, such as Fe, Co, and Ni. Using density functional theory calculations and angle- and spin-resolved photoemission spectroscopy, I...
Two-dimensional (2D) materials offer a versatile platform for exploring novel quantum phenomena and designing nanostructures with tailored functionalities. However, techniques such as photoemission spectroscopy, commonly used in 2D material studies, impose strict requirements for sample quality, uniformity, surface cleanliness, and size. Achieving these standards via traditional mechanical...
The study of chiral crystals is one of the frontiers in the field of topological materials. Weyl fermions with unique properties emerge in the absence of inversion and mirror symmetries [1]. Kramers-Weyl fermions, for example, are pinned at different high-symmetry points and surface arcs can connect them spanning over the entire Brillouin zone [2 - 4]. The physics of chiral crystals is further...
We study the electronic structure of bulk 1T-TaSe2 in the charge density wave (CDW) phase at low temperature. Our spatially and angle resolved photoemission (ARPES) data show insulating areas coexisting with metallic regions characterised by a chiral Fermi surface and weakly correlated low energy quasiparticle bands. Additionally, high-resolution laser ARPES reveals strong variations in the...
On the example of graphene, we will discuss various contributions to circular dichroism in angle-resolved photoemission (CD-ARPES) [1,2] which include phase shifts of the participating partial waves [3], the interatomic phase shifts [4], and the CD due to elastic scattering of an excited electron [5]. Multiple scattering calculations are performed using the EDAC cluster code [6] and the...
The unusual properties of superconductivity in magic-angle twisted bilayer graphene (MATBG) have sparked enormous research interest. However, despite the dedication of intensive experimental efforts and the proposal of several possible pairing mechanisms, the origin of its superconductivity remains elusive. Here, using angle-resolved photoemission spectroscopy with micrometer spatial...
Long-range electronic order descending from a metallic parent state constitutes a rich playground to study the intricate interplay of structural and electronic degrees of freedom. Kagome materials appeared as the perfect stage for such explorations. Specifically, RV6Sn6 (R = rare earth atom) bilayer kagome metals are topological systems with Dirac-like itinerant states, van Hove singularities...
The combination of nontrivial band topology & magnetism results in a wide variety of exotic electronic phases that -if realised at high temperatures- could revolutionise fields like spintronics or low-power consumption electronics. The new, second-generation ferrimagnetic compound Mn1+xSb2-xTe4 (0.1 ≤ x ≤ 1, abbreviated here as MST) promises to host the quantum anomalous Hall effect (QAHE) and...
