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Experimental signature of layer skyrmions and implications for band topology in twisted WSe 2 bilayers

Zhang, Fan [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000151419782)·Morales-Durán, Nicolás [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000286553620)·Li, Yanxing [Univ. of Texas, Austin, TX (United States)] (ORCID:0009000883096349)·Yao, Wang [Univ. of Hong Kong (Hong Kong)] (ORCID:0000000328834528)·Su, Jung-Jung [National Yang Ming Chiao Tung Univ. (Taiwan)]·Lin, Yu-Chuan [Pennsylvania State Univ., University Park, PA (United States); National Yang Ming Chiao Tung Univ] (ORCID:0000000349585073)·Dong, Chengye [Pennsylvania State Univ., University Park, PA (United States)] (ORCID:0000000185985758)·Liu, Xiaohui [Univ. of Texas, Austin, TX (United States)]·Chen, Fu-Xiang Rikudo [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000206392944)·Kim, Hyunsue [Univ. of Texas, Austin, TX (United States)]·Watanabe, Kenji [National Institute for Materials Science (NIMS), Tsukuba (Japan)] (ORCID:0000000337018119)·Taniguchi, Takashi [National Institute for Materials Science (NIMS), Tsukuba (Japan)] (ORCID:0000000214673105)·Li, Xiaoqin [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000222793078)·Robinson, Joshua A. [Pennsylvania State Univ., University Park, PA (United States)] (ORCID:0000000215137187)·Macdonald, Allan H. [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000335613379)·Shih, Chih-Kang [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000327347023)
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Abstract

Twisted homobilayers of transition-metal dichalcogenides have been established as an ideal platform for studying strong correlation phenomena, as exemplified by the recent discovery of fractional Chern insulator states in twisted MoTe 2 , as well as Chern insulators and unconventional superconductivity in twisted WSe 2 . In these systems, a non-trivial topology in the strongly layer-hybridized regime can arise from a spatial patterning of interlayer tunnelling amplitudes and layer-dependent potentials that yields a lattice of layer skyrmions. Here, in this work, we report experimental signatures of skyrmion textures in the layer degree of freedom of rhombohedral-stacked twisted WSe 2 homobilayers. Using scanning tunnelling spectroscopy that separately resolves the Γ-valley and K-valley moiré electronic states, we reveal opposite layer polarizations of the K valley at two different lattice sites with opposite stacking order within the moiré unit cell. These findings are consistent with the theoretically predicted layer-skyrmion texture. We also use our experimental results to parameterize a common continuum model of moiré bands in twisted bilayers, further establishing a direct correlation between the shape of the local density of states in real space and the topology of the topmost moiré band.

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Zhang, Fan [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000151419782), Morales-Durán, Nicolás [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000286553620), Li, Yanxing [Univ. of Texas, Austin, TX (United States)] (ORCID:0009000883096349), Yao, Wang [Univ. of Hong Kong (Hong Kong)] (ORCID:0000000328834528), Su, Jung-Jung [National Yang Ming Chiao Tung Univ. (Taiwan)], Lin, Yu-Chuan [Pennsylvania State Univ., University Park, PA (United States); National Yang Ming Chiao Tung Univ] (ORCID:0000000349585073), Dong, Chengye [Pennsylvania State Univ., University Park, PA (United States)] (ORCID:0000000185985758), Liu, Xiaohui [Univ. of Texas, Austin, TX (United States)], Chen, Fu-Xiang Rikudo [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000206392944), Kim, Hyunsue [Univ. of Texas, Austin, TX (United States)], Watanabe, Kenji [National Institute for Materials Science (NIMS), Tsukuba (Japan)] (ORCID:0000000337018119), Taniguchi, Takashi [National Institute for Materials Science (NIMS), Tsukuba (Japan)] (ORCID:0000000214673105), Li, Xiaoqin [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000222793078), Robinson, Joshua A. [Pennsylvania State Univ., University Park, PA (United States)] (ORCID:0000000215137187), Macdonald, Allan H. [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000335613379), Shih, Chih-Kang [Univ. of Texas, Austin, TX (United States)] (ORCID:0000000327347023). 2025-05-01. Experimental signature of layer skyrmions and implications for band topology in twisted WSe 2 bilayers. https://doi.org/10.1038/s41567-025-02876-y

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