Abstract
Considering a range of candidate quantum phases of matter, half-integer thermal conductance is believed to be an unambiguous evidence of non-Abelian states. It has been long known that such half-integer values arise due to the presence of Majorana edge modes, representing a significant step towards topological quantum computing. Here, we challenge this prevailing notion by presenting a comprehensive theoretical and experimental study where half-integer two-terminal thermal conductance plateau is realized employing integer quantum Hall states. Our proposed setup features a confined geometry of bilayer graphene, interfacing distinct particle and hole-like integer quantum Hall edges. Each segment of the device exhibits full charge and thermal equilibration. Our approach is amenable to generalization to other quantum Hall platforms, and may give rise to other values of fractional quantized transport. Our study demonstrates that the observation of robust non-integer values of thermal conductance can arise as a manifestation of mundane equilibration dynamics as opposed to underlying non-trivial topology.
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Acknowledgements
The authors thank Prof. Moty Heiblum for critical comments on the manuscript. U.R. and S.M. thank Arup Kumar Paul for useful discussions. We thank the International Centre for Theoretical Sciences (ICTS) for participating in the program - Condensed Matter meets Quantum Information (code: ICTS/COMQUI2023/9), where the collaboration was initiated. S.M. was supported by the Weizmann Institute of Science, Israel Deans fellowship through Feinberg Graduate School and the senior postdoctoral fellowship. Y.G. was supported by the InfoSys Chair, IISc, Bangalore. S.M. and Y. G. were also supported by the Minerva Foundation and grant no 2022391 from the United States–Israel Binational Science Foundation (BSF), Jerusalem, Israel. Ankur Das was supported by IISER, Tirupati Startup grant and ANRF/ECRG/2024/001172/PMS. M.G. has been supported by the Israel Science Foundation (ISF) and the Directorate for Defense Research and Development (DDR&D) through Grant No. 3427/21, the ISF Grant No. 1113/23, and the US-Israel Binational Science Foundation (BSF) through Grant No. 2020072. A.D. thanks the Department of Science and Technology (DST) and Science and Engineering Research Board (SERB), India, for financial support (SP/SERB-22-0387), (DST/NM/TUE/QM-5/2019), and also acknowledges funding through the Intensification of Research in High Priority Areas programme of the Science and Engineering Research Board (Grant No. IPA/2020/000034). A.D. also thanks CEFIPRA project SP/IFCP-22-0005. Growing the hBN crystals received support from the Japan Society for the Promotion of Science (KAKENHI grant nos. 19H05790, 20H00354 and 21H05233) to K.W. and T.T. The authors gratefully acknowledge the use of Blender (https://www.blender.org/) and Inkscape (https://inkscape.org/)—both free and open- source software—for the creation and refinement of figures presented in this work.
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K.W. and T.T. synthesized the hBN crystals. U.R. contributed to device fabrication, measurement, data acquisition, and analysis. S.C. contributed to the measurement. S.M., Ankur D., M.G., and Y.G. contributed to the development of theory, analysis and data interpretation. A.D. contributed in designing the experiment, data interpretation, and analysis. All the authors contributed to writing the manuscript.
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Roy, U., Manna, S., Chakraborty, S. et al. Half-integer thermal conductance in integer quantum Hall states. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69659-8
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DOI: https://doi.org/10.1038/s41467-026-69659-8
