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Topological quasiparticle with higher Chern number is promising to realize large-quantized photogalvanic effect. Here, the authors observe splitting of both topological surface and bulk states in a chiral crystal PtGa, suggesting multifold fermions with a maximal Chern number of ±4.

Fermionic currents of opposing chirality can be spatially filtered without the need for a magnetic field using the quantum geometry of topological bands in single-crystal PdGa.

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.

Chiral topological materials have been predicted to host orbital angular momentum monopoles, which can be useful for orbitronics applications. Now such monopoles have been imaged in chiral materials.

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.

Weyl semimetals exhibit a rich variety of transport phenomena, but it usually takes low temperatures and a strong magnetic field to realize them. Here, Quirk et al. show that when the ferromagnetic Weyl semimetal Co₂MnGa is polished to micron thicknesses, it develops a remarkable resistance anisotropy that has opposite directions on opposing crystal faces. They show that this unusual transport property, which is robust at room temperature and in a strong magnetic field, may be generated by distinct conducting states on the surfaces of these thin crystals.

The concept of quasi-symmetry—a perturbatively small deviation from exact symmetry—is introduced and leads to topological materials with strong resilience to perturbations.

Strong correlations between electrons in topological surface states drive the formation of surface van Hove singularities. These may be linked to charge density waves in the surface states.

In the Bloch or Neel domain walls in ferromagnets, the magnetization rotates smoothly from up to down, preserving its magnitude. Here, Lee et al show that Co3Sn2S2 exhibits a phase transition within its domain walls to a state in which the magnetization passes through zero rather than rotating as the wall is traversed.

A study combining spectroscopy and mathematical topology  reports the observation of linked node loops in a quantum magnet, with properties suggesting a Seifert bulk–boundary correspondence.

Although novel topological quasiparticles have recently been evidenced, their electrical transport properties remain elusive. Here, the authors report ultra-low resistivity down to 6 nΩcm at 2 K in MoP with a large mean free path, which hints on the exotic properties of triple point fermions.

Semimetals with the band structure exhibiting Dirac and Weyl crossings can show special electronic and magnetic properties. Here the authors explore the electronic properties of the type-II Weyl semimetals, MoP₂ and WP₂ with robust Weyl points which display very high magnetoresistance and conductivity.

Thermoelectric devices enable heat-electricity conversion, but achieving a large Nernst effect typically requires strong magnetic fields. Here, the authors demonstrate that YbMnBi₂, with its unique band topology and magnetic order, exhibits a remarkably high anomalous Nernst thermopower among magnetic materials, offering a promising route for efficient transverse thermoelectric applications.

Angle-resolved photoemission spectroscopy measurements reveal that CoSi and RhSi are nearly ideal topological conductors, with structural chirality and surface helicoid arcs of topological charge ±2 arising from bulk multifold chiral states.

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.

Heusler compounds, Weyl semimetals and the Berry phase are three current research fields of great interest. In this Review, we discuss the connection between the Berry phase and Weyl physics in the context of highly tunable Heusler compounds.

We report a high anomalous Nernst thermopower (\(S_{yx}^A\)) -value of ~6.0 µV K⁻¹ at room temperature in the ferromagnetic topological Heusler compound Co₂MnGa. The measured value is seven-times larger than any anomalous Nernst thermopower value ever reported for a conventional ferromagnet. The high anomalous Nernst effect originates from a large net Berry curvature near the Fermi level associated with nodal lines and Weyl points.