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Direct visualization of chiral effects in topological chiral semimetals remains elusive. Here, Sessi et al. demonstrate that quasiparticle scattering at impurities in the two enantiomers of PdGa gives rise to handedness dependent quantum interference patterns.

Previous studies have suggested that even in the absence of a graphene bandgap, a relaxation bottleneck at the Dirac point may allow for population inversion and lasing. Now, using time- and angle-resolved photoemission spectroscopy with femtosecond extreme-ultraviolet pulses, it is shown that interband excitations give rise to population inversion, suggesting that terahertz lasing may be possible.

The authors report that tensile strain applied to CsV₃Sb₅ strongly suppresses the charge-density-wave (CDW) gap, increases the mass of the fermions at the higher-order van Hove singularity (HO-VHS) and drives the energy of the HO-VHS towards the Fermi energy. Further, they suggest an important role of the HO-VHS in superconducting pairing.

The newly-synthesised α-RuI₃ has a much-debated ground state. Here, the authors demonstrate, using angle-resolved photoemission spectroscopy, that RuI₃ is a moderately correlated metal with an electronic band structure not having any in-plane symmetry, introducing the concept of pseudochirality to describe a similar band structure.

The identification of dark states—quantum states that do not interact with photons—in real materials may help to address many unsolved issues in condensed-matter physics. Now, they have been identified in palladium diselenide.

Spin-momentum locking is a fundamental property of condensed matter systems. Here, the authors evidence parallel Weyl spin-momentum locking of multifold fermions in the chiral topological semimetal PtGa.

Topological states in atomically thin quantum spin Hall insulators suffer from instability against environmental factors. Here, the authors devise a strategy to preserve topologically protected states in monolayer indenene through graphene intercalation.

The phase diagram of cuprates is mostly based on data for single- and double-layered compounds in which the CuO2 planes are affected by the disorder. Here the authors report new features in the phase diagram of cuprates with low disorder by investigating the inner CuO2 planes of the six-layered compound.

The charge density wave in Ta2NiSe7 cannot be easily explained by the Fermi surface nesting mechanism. Here, by using high-resolution ARPES, the authors reveal the absence of nesting at the primary vector q, but a backfolding at q and a possible nesting at 2q, suggesting a peculiar charge density wave state.

Angle-resolved photoemission evidence for a three-dimensional higher-order topological insulator is presented. This work demonstrates that stacking configurations can be utilized to realize different topological phases.

Sharp atomic interfaces between materials dictate the interface’s electronic properties. The authors use angle-resolved photoemission spectroscopy with a spatial resolution of ~500 nm to investigate the nanoscale electronic band structure and band alignment in a lateral heterostructure composed of WS₂ placed on alternating nano-stripes of monolayer and bilayer graphene.

Stacking of strongly correlated 2D materials is a promising route to realize exotic phases such as chiral superconductivity. Here, angle resolved photoemission spectroscopy measurements on a tantalum dichalcogenide polytype with alternately stacked layers reveal a finely structured Fermi surface arising from band hybridization with charge density wave star clusters.

AlPt is shown to be a chiral topological material with four-fold and six-fold degeneracies in the band structure. Fermi arc edge states span the whole Brillouin zone and their dispersion enables identification of the handedness of the chiral material.

Uniaxial strain is a powerful approach to tune material properties and select between nearly degenerate phases. Here, uniaxial strain is used to stabilize the elusive 6×1 charge ordered ground state of IrTe₂, revealing insights into its electronic structure and type-II topological Dirac states.