Also called TaS₂, 1T-TaS₂, 2H-TaS₂, TaSe₂
A material with a rich menu of electronic states. As it cools, 1T-TaS2 passes through several phases in which electrons clump into star-shaped clusters, ending as an insulator; a short laser or voltage pulse can flip it into a hidden metallic state that persists. That switchable memory makes it interesting for ultrafast electronics, and its ground state is a candidate quantum spin liquid. TaSe2 forms the same charge-density-wave patterns but stays metallic, which helps separate what the lattice distortion does from what electron correlations do.
They are coordination polyhedra. Only complete ones are drawn.
Three layers of 1T-TaS2 in its undistorted average cell. Each layer sits directly over the one below, so a single layer is the whole repeat: c = 5.86 Å. At room temperature and below, the real crystal carries a charge-density wave on top of this cell. Cell from Hägg and Schönberg, Arkiv för Kemi 7, 371 (1954); COD 1537360.
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Correlations and stacking compete: DFT+U or DMFT on a single Star-of-David layer gives a Mott insulator, but interlayer dimerisation in bulk can open a gap without correlations. Faithful models need the 13-atom charge-density-wave supercell, the stacking sequence and spin–orbit coupling.
Resistivity hysteresis between ~180 K on cooling and ~220 K on warming is the fingerprint of the commensurate transition in bulk; it shifts and broadens in thin flakes. STM images the Star-of-David pattern directly, and ultrafast pump–probe and ARPES follow the charge-density-wave dynamics.
Offers non-volatile resistive switching on picosecond timescales, but many useful phases sit below room temperature and device reproducibility is unproven.
The newest items tagged TaS2, TaSe2, from the news feed updated 5 Oct 2026.
Broadband infrared photodetectors operating at room temperature are fundamentally limited by the lack of efficient gain mechanisms for weak optical signals. Phase-transition materials provide a promising route for intrinsic signal amplification owing to their extreme sensitivity near critical transition boundaries.…
Electronic phases that lie outside the equilibrium ground state offer a route to explore competing configurations in correlated materials. In 1T-TaS2, ultrafast excitation accesses a metallic hidden phase that is distinct from the commensurate insulating ground state. Here we use angle-resolved photoemission…
Chiral helimagnets based on intercalated transition-metal dichalcogenides, characterized by nanoscale spin ordering, provide a powerful route to engineer chiral spin textures (e.g., the topologically protected magnetic solitons) and explore emergent electronic functionalities associated with their surface and interface…
Polarons are quasiparticles composed of excess electrons and local lattice distortions that are crucial for understanding many-body physics. However, atomic-scale observation and manipulation of an intrinsic polaron in strongly correlated systems still remain elusive. Here, we report the discovery and manipulation of a…
The tunability and twist engineering of van der Waals materials enable the emergence of electronic states not present in individual monolayers. Among them, monolayer 1T-TaS2 is a well-known Mott insulating system, whose star-of-David charge density wave reconstruction realizes an emergent triangular lattice of local…
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