Łucja Kipczak

The authors initiate the correction to the original publication.1

Monolayers (MLs) of semiconducting transition metal dichalcogenides emit light very efficiently and display rich spin-valley physics, with gyromagnetic ( g ) factors of about − 4 . Here, we investigate how these properties can be tailored by alloying. Magneto-optical spectroscopy is used to reveal the peculiar properties of excitonic complexes in Mo x W 1 − x Se 2 MLs with different metal concentrations. We show that the alloys feature extremely high g factors for neutral excitons, that change gradually with the composition up to reaching values of the order of − 10 for x ≈ 0.2 . First-principles calculations quantitatively identify the alloy-induced mixing between different conduction band valleys as the underlying mechanism originating the anomalous composition dependence of the neutral exciton g factor. The theoretical framework also suggests a high strain sensitivity of the alloys, making them promising candidates for tailor-made optoelectronic devices.

Two-dimensional (2D) layered magnetic materials (LMMs) are a newly emerging class of van der Waals materials, opening new opportunities to study magneto-excitonic coupling. The air-stable, structurally and optically anisotropic A-type antiferromagnetic chromium sulfur bromide (CrSBr) is one of the most prominent examples of such LMMs. We investigate photoluminescence (PL) and PL excitation of mono-to tri-layers CrSBr and find that it exhibits a unique duplexity, supporting both Frenkel-and Wannier-Mott-like excitons. Our magneto-optical experiments reveal a similar excitonic response from the mono-and trilayer systems and a completely different signature in the bilayer flake. This shows a different origin of the low-lying excitonic species (A, A' and B) in the band structure. We confirm the robustness of the magneto-excitonic coupling in few-layer CrSBr. Our work enables a more comprehensive exploration of the dual excitonic behavior in 2D materials.

Magnetic proximity effect observed on the WSe₂/CrCl₃ heterostructure as the brightening of the dark exciton from WSe₂ ML without external magnetic field is applied.

Optically dark states play an important role in the electronic and optical properties of monolayers (MLs) of semiconducting transition metal dichalcogenides. The effect of temperature on the in‐plane‐field activation of the neutral and charged dark excitons is investigated in a WSe ₂ ML encapsulated in hexagonal BN flakes. The brightening rates of the neutral dark ( X ^D ) and grey ( X ^G ) excitons and the negative dark trion ( T ^D ) differ substantially at particular temperature. More importantly, they weaken considerably by about 3–4 orders of magnitude with temperature increased from 4.2 K to 100 K. The quenching of the dark‐related emissions is accompanied by the two‐order‐of‐magnitude increase in the emissions of their neutral bright counterparts, i . e . neutral bright exciton ( X ^B ) and spin‐singlet ( T ^S ) and spin‐triplet ( T ^T ) negative trions, due to the thermal activations of dark states. Furthermore, the energy splittings between the dark X ^D and T ^D complexes and the corresponding bright X ^B , T ^S , and T ^T ones vary with temperature rises from 4.2 K to 100 K. This is explained in terms of the different exciton–phonon coupling for the bright and dark excitons stemming from their distinct symmetry properties.

Ternary two-dimensional (2D) transition metal chalcogenides have gained immense attention because of their ability to overcome the intrinsic limitations of their binary counterparts. Layered 2D materials are important for future electronic and photonic devices owing to their low structural symmetry and in-plane anisotropy with tunable bandgap. Herein, the electronic structure and detailed vibrational properties of bulk ZrGeTe4 layered single crystals were investigated using angle-resolved photoemission spectroscopy (ARPES) and Raman scattering (RS). The ARPES results revealed an anisotropic Fermi surface of different momentum along kx and ky from the zone center and an anisotropic band structure with varying band curvatures along the high-symmetry directions. Furthermore, the RS of ZrGeTe4 was investigated under different polarizations and varying temperatures. The polarized RS exhibited twofold and fourfold symmetry orientations in different configurations, revealing the anisotropic phonon dispersions for bulk ZrGeTe4. The observed softening of Raman modes was corroborated with the anharmonic phonon dispersion, which was further supported by our third-order force constant calculations of thermal transport using density functional theory. Low lattice thermal conductivity with increasing temperature is linked with enhanced phonon–phonon scattering, which is evident from the decreased phonon lifetime and peak linewidth. In addition to these fundamental aspects, the anisotropic nature and unique layered structure of such materials reveal their bright future for next-generation nanoelectronic applications.

Moiré excitons (MXs) are electron-hole pairs localised by the periodic (moiré) potential forming in two-dimensional heterostructures (HSs). MXs can be exploited, e.g., for creating nanoscale-ordered quantum emitters and achieving or probing strongly correlated electronic phases at relatively high temperatures. Here, we studied the exciton properties of WSe₂/MoSe₂ HSs from T = 6 K to room temperature using time-resolved and continuous-wave micro-photoluminescence also under a magnetic field. The exciton dynamics and emission lineshape evolution with temperature show clear signatures that MXs de-trap from the moiré potential and turn into free interlayer excitons (IXs) for temperatures above 100 K. The MX-to-IX transition is also apparent from the exciton magnetic moment reversing its sign when the moiré potential is not capable of localising excitons at elevated temperatures. Concomitantly, the exciton formation and decay times reduce drastically. Thus, our findings establish the conditions for a truly confined nature of the exciton states in a moiré superlattice with increasing temperature and photo-generated carrier density.