Crossing the Insulator-to-Metal Barrier with a Thiazyl Radical Conductor

The layered-sheet architecture of the crystal structure
of the fluoro-substituted oxobenzene-bridged bisdithiazolyl radical
FBBO affords a 2D π-electronic structure with a large calculated
bandwidth. The material displays high electrical conductivity for
a f = 1/2 system, with σ­(300
K) = 2 × 10–2 S cm–1. While
the conductivity is thermally activated at ambient pressure, with Eact = 0.10 eV at 300 K, indicative of a Mott
insulating state, Eact is eliminated at
3 GPa, suggesting the formation of a metallic state. The onset of
metallization is supported by infrared measurements, which show closure
of the Mott-Hubbard gap above 3 GPa.

氟取代氧苯桥联双二噻唑基自由基（FBBO）的晶体结构具有层片状架构，其呈现二维π电子结构，且经计算拥有较大的能带宽度。该材料在f=1/2体系中展现出较高的电导率，300K下的电导率σ(300K)=2×10⁻² S·cm⁻¹。常压下其电导率表现为热激活特性，300K时活化能Eact=0.10 eV，这表明体系处于莫特绝缘态；当压力达到3吉帕斯卡（GPa）时，活化能消失，暗示体系形成了金属态。红外测量结果进一步佐证了金属化过程：当压力高于3 GPa时，莫特-哈伯德能隙发生闭合。