5 research outputs found
Topological band inversion in HgTe(001): surface and bulk signatures from photoemission
HgTe is a versatile topological material and has enabled the realization of a
variety of topological states, including two- and three-dimensional (3D)
topological insulators and topological semimetals. Nevertheless, a quantitative
understanding of its electronic structure remains challenging, in particular
due to coupling of the Te 5p-derived valence electrons to Hg 5d core states at
shallow binding energy. We present a joint experimental and theoretical study
of the electronic structure in strained HgTe(001) films in the 3D
topological-insulator regime, based on angle-resolved photoelectron
spectroscopy and density functional theory. The results establish detailed
agreement in terms of (i) electronic band dispersions and orbital symmetries,
(ii) surface and bulk contributions to the electronic structure, and (iii) the
importance of Hg 5d states in the valence-band formation. Supported by theory,
our experiments directly image the paradigmatic band inversion in HgTe,
underlying its non-trivial band topology
Observation of flat moir\'e bands in twisted bilayer WSe
The recent observation of correlated phases in transition metal
dichalcogenide moir\'e systems at integer and fractional filling promises new
insight into metal-insulator transitions and the unusual states of matter that
can emerge near such transitions. Here, we combine real- and momentum-space
mapping techniques to study moir\'e superlattice effects in 57.4
twisted WSe (tWSe). Our data reveal a split-off flat band that derives
from the monolayer states. Using advanced data analysis, we directly
quantify the moir\'e potential from our data. We further demonstrate that the
global valence band maximum in tWSe is close in energy to this flat band
but derives from the monolayer K-states which show weaker superlattice effects.
These results constrain theoretical models and open the perspective that
-valley flat bands might be involved in the correlated physics of
twisted WSe
Flat Gamma Moiré Bands in Twisted Bilayer WSe2 (Source Data)
AbstractSource data of manuscript "Flat Gamma Moiré Bands in Twisted Bilayer WSe2" published in Physical Review Letter
Electronic structure of the highly conductive perovskite oxide SrMoO<sub>3</sub>
We use angle-resolved photoemission to map the Fermi surface and quasiparticle dispersion of bulk-like thin films of SrMoO grown by pulsed laser deposition. The electronic self-energy deduced from our data reveals weak to moderate correlations in SrMoO, consistent with our observation of well-defined electronic states over the entire occupied band width. We further introduce spectral function calculations that combine dynamical mean-field theory with an unfolding procedure of density functional calculations and demonstrate good agreement of this approach with our experiments