Sign-changeable spin-filter efficiency in linear carbon atomic chain

It is well known that there is spin-filter efficiency (SFE) of a linear carbon atomic chain. In this article, we examine the quantum transport calculations of a linear carbon atomic chain connected to two half-planar graphene electrodes by using the first-principle method and reveal for the first time that sign of the SFE of such carbon atomic chain is changeable with the bias. This makes the carbon atomic chains attractive to potential application of spintronics.