(TaSe₄)₂I (Tantalum Selenide Iodide)

A quasi-one-dimensional van der Waals compound, space group I422, consisting of TaSe₄ chains running along the c-axis that are weakly linked by iodine. The chains host a well-defined charge density wave (CDW) below ~263 K, and (TaSe₄)₂I is regarded as a candidate axion insulator, in which a sliding CDW couples to the electromagnetic response to produce an axionic contribution; a giant current-driven CDW sliding and anomalous transport have been reported, making it a central platform for studying topological CDW physics and axion electrodynamics.

Sample specifications: Individual crystals measure approximately 3~5 mm, with a purity of up to 99.9999% (6N), and multiple high-quality single-crystal pieces included in each package.

Exfoliation: Difficult — strong interlayer bonding; mechanical exfoliation typically yields thick flakes, and ultrathin flakes are challenging to isolate.

Growth method: Chemical vapor transport (CVT).