Abstract
Fractionalization of the electron charge e is one of the most striking phenomena arising from strong electron–electron interactions. A celebrated example is the emergence of anyons with fractional charges in fractional quantum Hall effect (FQHE) states1,2,3,4,5,6,7,8,9,10,11,12,13. Recently, zero-field fractional Chern insulators (FCIs)14,15,16,17,18,19, lattice analogues of the FQHE states that form without Landau levels, have been realized20,21. FCIs provide a unique platform to investigate anyons, yet their detection remains a challenge. Here we report the observation of anyon–trions, a new type of excitonic complex formed by binding a trion with a fractional charge in twisted MoTe2 bilayers. Photoluminescence spectroscopy of quantum-confined excitons reveals emergent peaks that appear only within slightly doped FCI states. The new spectral features are red-shifted relative to the trions in undoped FCIs, but share the same electric field, temperature and magnetic field dependence. These observations suggest their origin as trions binding with elementary quasi-particles, that is, anyon–trions. Crucially, the ratio of binding energies between the anyon–trions in the −2/3 and −3/5 FCI states matches the expected fractional charge ratio of e/3 to e/5. This provides strong evidence for fractional charges in FCI—an essential property of anyons. Our results address a fundamental question in FCI physics and establish trion spectroscopy as a powerful probe of fractionally charged excitations, complementary to transport- and tunnelling-based approaches.
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Acknowledgements
We are deeply grateful to M. Heiblum and Y. Zheng for their thoughtful and constructive feedback on the manuscript. This project is supported mainly by the US Department of Energy (DoE), Office of Science, Basic Energy Sciences (BES), under the award DE-SC0018171. The fabrication and measurement are supported partially by a Vannevar Bush Faculty Fellowship (Award number N000142512047). Bulk MoTe2 crystal growth and characterization is supported by Programmable Quantum Materials, an Energy Frontier Research Center funded by DoE BES under award DE-SC0019443. T.C. acknowledges the support of the DoE, Office of Basic Energy Sciences, under Contract No. DE-SC0025327 for part of the theoretical analysis. D.X. acknowledges support from DoE BES under the award DE-SC0012509. K.W. and T.T. acknowledge support from the JSPS KAKENHI (grant nos. 21H05233 and 23H02052), the CREST (JPMJCR24A5), JST and World Premier International Research Center Initiative (WPI), MEXT, Japan. X.X. acknowledges support from the State of Washington funded Clean Energy Institute and from the Boeing Distinguished Professorship in Physics.
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X.X. and W.L. conceived the experiment. W.L. performed device fabrication and measurements, with assistance from C.W.B. W.L., A.I., T.C., D.X. and X.X. analysed and interpreted the results. T.T. and K.W. synthesized the hBN crystals. C.H. and J.-H.C. grew and characterized the bulk MoTe2 crystals. X.X., W.L. and D.X. wrote the paper with input from all authors. All authors discussed the results.
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Extended data figures and tables
Extended Data Fig. 1 Real space photoluminescence (PL) and reflectance contrast mapping.
a, Spatial map of spectrally integrated PL intensity for the quantum confined trions. b, Spatial map of spectrally integrated PL intensity for the free trions. Three regions, twisted monolayer/bilayer MoTe2 (tML/BL), twisted monolayer/monolayer MoTe2 (tML/ML), and twisted bilayer/monolayer MoTe2 (tBL/ML) are marked and separated by the white dashed lines, with an uncertain of ~ 1 µm limited by the laser beam spot size. The circles indicate the spatial location of traps. The quantum confined trion emission is localized on the boundary of an area dominated by free trion PL. We do not observe trapped trions located clearly within the bulk region. c, Spatial map of lowest energy resonances in reflectance contrast spectra. The twisted trilayer regions exhibit lower energy resonances than the twisted bilayer region. d, Representative reflectance contrast spectra of twisted monolayer/bilayer MoTe2 (left), twisted monolayer/monolayer MoTe2 (middle), and twisted bilayer/monolayer MoTe2 (right) at charge neutrality. The black arrows indicate the lowest energy resonances.
Extended Data Fig. 2 Reflective magnetic circular dichroism (RMCD) characterization of the ferromagnetic phase diagram.
a, RMCD signal versus filling ν and electric fields. b, ΔRMCD signal (the hysteretic component of RMCD) versus ν and magnetic fields μ0H. RMCD and ΔRMCD span from ν = −1.2 to −0.38 at zero magnetic field.
Extended Data Fig. 3 Fan diagram obtained from integrated PL intensity over trapped trions.
a, PL intensity plot versus filling ν and photon energy at selected magnetic fields. The dashed lines are guides to the eye for FCI states at ν = −2/3, −3/5, −4/7, −4/9, −3/7, and −2/5. b, Optically detected fan diagram from spectrally integrated PL intensity versus μ0H and filling factor ν. The additional feature (−0.685 <ν < −0.675) highlighted by the white arrow is the anyon trion. c, Top panel, optically detected fan diagram from tracking the peak energy of the quantum confined trion versus v and magnetic field, reproduced from the main text Fig. 1f for comparison with b. The bottom panel shows the corresponding Wannier diagram, where the FCI states are traced and overlaid with the expected Streda slope. Linear fits yield C = −0.63(4), −0.58(4), −0.53(3), −0.43(2), −0.41(3), and −0.38(4) for ν = −2/3, −3/5, −4/7, −4/9, −3/7, and −2/5, respectively.
Extended Data Fig. 4 Observation of anyon trions from additional potential traps.
a-f, PL of quantum confined trions from potential trap-4 to 9 versus v and photon energy. Dashed boxes highlight the FCI states with anyon-trions.
Extended Data Fig. 5 Intensity anticorrelation between FCI-trion and anyon-trion.
a, Time trace of the normalized peak intensity of the anyon trion (blue) and FCI trion (red), plotted as their ratio to the sum of the PL intensity of anyon-trion and FCI-trion. Green (black) arrows mark the anticorrelated intensity fluctuations (overall intensity switch) between the two trion species, while the total intensity remains nearly constant. b, Another set of time-dependent PL measurements reveals correlated energy fluctuations. The FCI-trion intensity increases whereas the anyon-trion intensity weakens over time.
Extended Data Fig. 6 Electric field dependence of FCI- and anyon-trions.
a, PL versus electric field at doping with v at -2/3 FCI-trion (left panel), and anyon-trion (middle panel), which are added together to yield the right panel. The data is from trap 2. b, c, Same as a but for trap 1 (b) and 6 (c). FCI- and anyon-trions exist in the same electric field range.
Extended Data Fig. 7 Binding energies of anyon-trions from additional potential traps.
a-f, Left panels: PL spectra of the −2/3 anyon-trion (red, v = −0.68) and FCI-trion (blue, v = −2/3). Right panels: PL spectra of the −2/3 anyon-trion (red, v = −0.61) and FCI-trion (blue, v = −3/5). The data are from six different potential traps (traps−2, 6 to 8, 10 and 11).
Extended Data Fig. 8 Quantum confined trions originated from multiple traps.
a,b, Optimized PL of quantum confined trions from the lower-energy trap (a, reproduced from Fig. 2e) and from both traps (b). The two appreciable trion plateaus corresponding to the −2/3 state arise from separate traps. Upon optimizing emission from both traps, two anyon-trion features (indicated by the white and green arrows) are appreciable.
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Li, W., Wang Beach, C., Hu, C. et al. Signatures of fractional charges via anyon–trions in twisted MoTe2. Nature (2026). https://doi.org/10.1038/s41586-026-10101-w
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DOI: https://doi.org/10.1038/s41586-026-10101-w
