Theoretical Studies of Sandwich Molecular Wires with Europium and Boratacyclooctatetraene Ligand and the Structure on a H-Ge(001)-2x1 Surface

The structural, electronic, and magnetic properties of two kinds of boron-doped europium cydooctatetraene sandwich molecular wires (SMWs), [EuCOTB](infinity) and [Eu-COTB-Eu-COT](infinity) (Eu = europium, COT = cydooctatetraene = C8H8, COTB = boratacyclooctatetraene), are investigated with spin-polarized density functional theory. Both SMWs are of high stability and ultrahigh magnetic moments, and the [Eu-COTB-Eu-COT](infinity) SMW even owns half-metallic characteristics. Our calculations further reveal that the [Eu-COTB-Eu-COT] SMW anchored on a semiconductor germanium surface is a quasi-half metallic ferromagnet, and it can be tuned into full half-metallicity under a mild external electric field. The unveiled intriguing properties here suggest that the boron-doped europium cydooctatetraene SMWs may be compelling candidates for future spintronics devices.