biostudies-literatureFarhang CGordon and Betty Moore Foundation (Gordon E. and Betty I. Moore Foundation)National Science Foundation (NSF)7867https://www.ebi.ac.uk/biostudies/studies/S-EPMC12375086biostudies-literatureUnknown16(1)Nematicity, spontaneous breaking of rotational symmetry, is a ubiquitous phenomenon in correlated quantum matter. Here we show a phase transition in high-quality ScV6Sn6 bilayer kagome metal at a temperature T* , occurring seven Kelvins below the charge density wave transition at TCDW , as indicated by thermodynamic, transport, and optical measurements. This emerging intermediate phase does not exhibit spontaneous time-reversal-symmetry breaking, as evidenced by zero-field Sagnac interferometry. However, it displays a strong, spontaneous in-plane anisotropy between T* and TCDW , revealed by transport and optical polarization rotation measurements. A pronounced depolarization effect detected by the Sagnac interferometer further confirms its nematic nature. Unlike AV3Sb5, this phase, alongside the recently discovered intra-unit cell nematic order at lower temperatures, presents a diverse landscape of nematicities at multiple length and temperature scales. Our findings highlight ScV6Sn6 as a prime candidate for realizing symmetry-breaking phases driven by charge density competition, kagome physics, and Van Hove singularities.Nature communicationsDiscovery of an intermediate nematic state in a bilayer kagome metal ScV₆Sn₆.PMC12375086GBMF10276DMR-2419425Li JXia JLu WMozaffari SZhang YMadhogaria RPMandrus DFarhang CMeier WRWu YfalseDiscovery of an intermediate nematic state in a bilayer kagome metal ScV₆Sn₆.Nematicity, spontaneous breaking of rotational symmetry, is a ubiquitous phenomenon in correlated quantum matter. Here we show a phase transition in high-quality ScV6Sn6 bilayer kagome metal at a temperature T* , occurring seven Kelvins below the charge density wave transition at TCDW , as indicated by thermodynamic, transport, and optical measurements. This emerging intermediate phase does not exhibit spontaneous time-reversal-symmetry breaking, as evidenced by zero-field Sagnac interferometry. However, it displays a strong, spontaneous in-plane anisotropy between T* and TCDW , revealed by transport and optical polarization rotation measurements. A pronounced depolarization effect detected by the Sagnac interferometer further confirms its nematic nature. Unlike AV3Sb5, this phase, alongside the recently discovered intra-unit cell nematic order at lower temperatures, presents a diverse landscape of nematicities at multiple length and temperature scales. Our findings highlight ScV6Sn6 as a prime candidate for realizing symmetry-breaking phases driven by charge density competition, kagome physics, and Van Hove singularities.2025-01-01T00:00:00Z2025 Aug2026-05-10T04:26:29.559Z2026-04-08T01:29:22.773ZS-EPMC123750864084930810.1038/s41467-025-63294-5