The Spectroscopic Atlas of Excitonic Complexes in hBN-Encapsulated S-TMD Monolayers: From Excitons to Oxcitons and Beyond

Maciej R. Molas

Home/Archive/arXiv

arXiv · 2610.29081

The Spectroscopic Atlas of Excitonic Complexes in hBN-Encapsulated S-TMD Monolayers: From Excitons to Oxcitons and Beyond

Maciej R. Molas

View original source ↗Read source document ↗Export metadata ↓

Abstract

Hexagonal boron nitride (hBN) encapsulation has transformed the optical spectroscopy of semiconducting transition-metal dichalcogenide monolayers (MLs) by suppressing extrinsic disorder and enabling the resolution of an increasingly complex hierarchy of excitonic states. This Review provides a spectroscopy-oriented framework for understanding and identifying excitonic complexes in hBN-encapsulated Mo- and W-based MLs and their alloys. The discussion covers bright and dark excitons, Rydberg states, charged excitons, biexcitons, phonon-assisted replicas, and higher-order Fermi-sea many-body states, including hexcitons and oxcitons, with an emphasis on the experimental signatures that distinguish them. Particular attention is given to the combined use of photoluminescence and absorption-related spectroscopy, electrostatic gating, polarization analysis, excitation-power and temperature dependences, magnetic fields, and time-resolved measurements to establish microscopic assignments. The role of alloying as an additional degree of freedom for engineering the excitonic hierarchy, spin-valley configuration, and magneto-optical response is also highlighted. By organizing the rapidly expanding phenomenology around experimentally accessible fingerprints rather than individual material systems, this Review aims to provide a practical and broadly applicable guide for identifying, comparing, and engineering excitonic states in high-quality two-dimensional semiconductors.

Explore related subjects

cond-mat.mes-hall cond-mat.mtrl-sci

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Maciej R. Molas. 2026-10-21. The Spectroscopic Atlas of Excitonic Complexes in hBN-Encapsulated S-TMD Monolayers: From Excitons to Oxcitons and Beyond. https://arxiv.org/abs/2610.29081

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Electrostatic edge effects versus edge doping in graphene nanoribbons: a scanning gate microscopy and modelling study

The charge neutrality point (CNP) of graphene nanoribbons (GNRs) patterned by oxygen plasma etching moves towards zero as the ribbon narrows and, on 300 nm SiO2, changes sign below a crossover width of ~ 50 nm: an observation previously attributed to n-type edges surrounding a p-type bulk. We test this edge-doping hypothesis in three ways. First, finite element modelling of complete GNR transistors with uniform doping shows that fringing of the gate field at the edges reproduces the trend of the measured CNP with width down to ~ 50nm without any edge doping, while producing a bias-dependent inversion of the carrier type at the edges that mimics n-type edges in scanned-probe measurements. Second, fitting the CNP of ribbons on 90 nm and 300 nm SiO2 with the gate capacitance of a finite strip, which fixes the electrostatic contribution with no adjustable parameter other than the bulk doping, shows that fringing accounts for most of the width dependence and isolates the remainder as an edge charge. This is acceptor-like (0.24 e/nm per edge) in the present ribbons, which therefore have no n-type edges, and donor-like but small in devices on 300 nm SiO2; no single edge-charge, field-coupled or contact-doping mechanism describes both. Third, scanning gate microscopy finds no edge contrast of the sign expected for n-type edges. The width dependence of the CNP is therefore predominantly electrostatic, and n-type edges are not an intrinsic consequence of oxygen-plasma etching. A design map shows that fringing dominates the width dependence whenever the gate dielectric is thicker than 30-50 nm, whereas in scaled high-K transistors, edge charge dominates and would shift the threshold voltage of a 10 nm ribbon by ~ 0.1-0.15 V. Fitting the CNP versus width with the strip capacitance provides a simple test for edge doping in any gated two-dimensional nanostructure

cond-mat.mes-hall↗

arXiv2026

Parity-driven RKKY decoupling and anomalous $1/R$ Dzyaloshinskii-Moriya interaction in odd-parity magnets

Unconventional odd-parity magnets, characterized by an odd-parity momentum-dependent spin splitting, offer a fundamentally distinct paradigm for non-collinear spintronics. Here, we theoretically investigate the Ruderman-Kittel-Kasuya-Yosida indirect exchange in two-dimensional odd-parity magnets subjected to Rashba spin-orbit coupling. Using an analytical real-space Green's function formalism, we uncover a parity-driven spatial decoupling in the magnetic response. Because of the odd-parity exchange field, the out-of-plane Ising interaction is structurally insulated from the macroscopic magnetic modulation, oscillating isotropically at the shifted Fermi wavevector. Conversely, the in-plane Heisenberg components exhibit pronounced, directionally tunable spatial beating. Beyond collinear exchange, the hybridized bands generate a highly tunable, three-component Dzyaloshinskii-Moriya interaction alongside symmetric off-diagonal anisotropies. We reveal that the out-of-plane chiral twisting is driven by the massive, nonrelativistic momentum shift, while the in-plane chiral components are relativistic. Furthermore, the competition between the nodal geometry and the Rashba gap drives an anomalous, dimension-reducing crossover, in which the in-plane chiral components follow a 1D-like $1/R$ spatial decay along the nodal lines over an extended intermediate-distance window before ultimately recovering the conventional 2D $1/R^2$ asymptote. We demonstrate that these findings hold universally across the odd-parity class by explicitly generalizing our framework to $f$-wave magnets. Finally, numerical tight-binding calculations verify the striking robustness of this parity-driven decoupling against both scalar and random magnetic exchange disorder. These findings establish odd-parity magnets as promising platforms for engineering robust, directionally tunable non-collinear spin textures.

cond-mat.mes-hall↗

arXiv2026

Ferroelastic Reversal Magnon Thermal Hall Effect in a Fully Compensated Ferrimagnet

Magnons offer a charge-neutral channel for spin and heat transport, yet reversible and nonvolatile control of their thermal Hall response poses a fundamental challenge in systems with zero net magnetization. Here, we establish ferroelastic switching as an effective route to manipulate magnonic transverse responses in fully compensated ferrimagnets. A minimal Heisenberg-Dzyaloshinskii-Moriya model reveals that ferroelastic switching can re-orientate the lattice anisotropy, which reconstructs the chirality-resolved magnon bands and Berry curvature distribution. Consequently, the two orthogonal fully compensated ferrimagnetic variants related by [C2||C4z] exhibit magnon thermal Hall responses with opposite signs, whereas the response vanishes in the intermediate altermagnetic phase. First-principles calculations further identify monolayer V2SSe as a promising material candidate for realizing the proposed ferroelastic control of transverse magnon transport. Remarkably, ferroelastic switching drives a dual magnonic-electronic band reconstruction, enabling nonvolatile reversal of the magnon thermal Hall effect while producing anisotropic orbital Hall responses and distinct magneto-optical spectra as complementary transport and optical fingerprints. Our findings establish ferroelasticity as an effective route to nonvolatile magnon control and multichannel state identification in zero net magnetization systems.

cond-mat.mes-hall↗