A new ambient-pressure organic superconductor (TMET-STF)2BF4 [TMET-STF = trimethylene(ethylenedithio)diselenadithiafulvalene]

Abstract

Under ambient pressure, the cation radical salt (TMET-STF) ₂ BF ₄ , where the tight-binding band calculation suggests coexistence of one- and two-dimensional Fermi surfaces associated with two different conduction layers within the crystal, shows two types of resistivity anomalies around 115 and 13 K, followed by a superconducting transition at 4.1 K (onset).