CsV₂Te₂O (Cesium Vanadium Oxytelluride)

CsV₂Te₂O is a layered vanadium oxytelluride of the '1221' oxychalcogenide family, crystallizing in the tetragonal P4/mmm structure with two-dimensional V₂O square nets sandwiched between tellurium layers and separated by Cs layers (as grown, the crystals are typically slightly Cs-deficient, Cs_1-δV₂Te₂O with δ ≈ 0.2). It is the first material in which hidden altermagnetism has been experimentally demonstrated: its G-type collinear antiferromagnetic order (Néel temperature near room temperature, ~257–293 K) stacks two-dimensional altermagnetic layers with alternating local spin polarizations, so the bulk bands remain spin-degenerate while each layer carries a d-wave, momentum-dependent spin splitting — verified by neutron diffraction together with spin-resolved ARPES. First-principles calculations find a robust Néel-type antiferromagnetic ground state with orbital-selective spin splitting at the Fermi level, and a secondary transition near 70 K. CsV₂Te₂O single crystals provide a unique platform for studying hidden altermagnetism, layered spin polarization, and altermagnetic spintronics.

Growth method: Self-flux growth. Note: the crystals are moisture-sensitive; storage under inert atmosphere or vacuum is recommended.

Specifications: Single crystal, typical size ~1–1.5 mm; purity up to 99.9999% (6N). Multiple high-quality single-crystal pieces are included in each package.

Exfoliation difficulty: Moderate — a layered van der Waals crystal that can be mechanically cleaved/exfoliated, although the ionic interlayer bonding makes isolating ultrathin flakes more demanding than in typical van der Waals materials.

Note: A small amount of potassium (~5%) may remain in the crystals: potassium is removed by deintercalation during synthesis, and its complete removal cannot always be guaranteed. Like other crystals of this family, the as-grown material is typically slightly Cs-deficient (Cs_1-δV₂Te₂O, δ ≈ 0.2).