Conductance and spin-filter effects of oxygen-incorporated Au, Cu, and Fe single-atom chains

Abstract

We studied the spin-polarized electron transport in oxygen-incorporated Au, Cu, and Fe single-atom chains (SACs) by first-principles calculations. We first investigated the mechanism responsible for the low conductance (<1G 0) of the Au and Cu SACs in an oxygen environment reported in recent experiments. We found that for the Au SACs, the low conductance plateau around 0.6G 0 can be attributed to a distorted chain doped with a single oxygen atom, while the 0.1G 0 conductance comes from a linear chain incorporated with an oxygen molecule and is caused by an antibonding state formed by oxygen's occupied frontier orbital with d z orbitals of adjacent Au atoms. For the Cu SACs, the conductance about 0.3G 0 is ascribed to a special configuration that contains Cu and O atoms in an alternating sequence. This exhibits an even-odd conductance oscillation with an amplitude of $0.1G 0. In contrast, for the alternating Fe-O SACs, conductance overall decreases with an increase in O atoms and it approaches nearly zero for the chain with more than four O atoms. While the Cu-O SACs behave as perfect spin filters for one spin channel due to the half metallic nature, the Fe-O SACs can serve as perfect spin filters for two spin channels depending on the polarity of the applied gate voltage. V

Highly conductive and complete spin filtering of nickel atomic contacts in a nitrogen atmosphere

“…In addition, a smaller conductance of about 0.5G 0 is found in Ni/CO/Ni 37 in the break junction experiment. Moreover, in the case of Fe/O 2 /Fe, rather low conductance and SP of about 0.13G 0 and 50% are found 38 . Very recently, R. Vardimon et al 21 Motivated by promising results with the N 2 molecule, we also investigated the transport properties of Ni atomic contacts in the presence of CO and NO molecules in the parallel configuration (also fully relaxed).…”

Mechanisms of jump to contact and conductance plateau formation in copper atomic junctions in vacuum and aqueous environments

“…Adsorbed gas atoms or molecules may cause a deviation from integer values in the conductance at room temperature even at ultrahigh vacuum conditions. For this reason, the influence of light gas atoms and molecules on the structural and electronic properties of metallic junctions and point contacts has been widely studied experimentally [18][19][20][21][22][23][24][25][26][27][28] and theoretically [29][30][31][32][33][34]. For instance, using the MCBJ technique it has been shown that oxygen atoms can be incorporated in noble metal (Au, Ag, Cu) atomic chains, leading to a considerable reduction in conductance for Ag and Cu chains and retaining the conductance near one quantum unit (1g 0 = 2e 2 /h) for Au atomic chains [23,25].…”

Thermoelectric voltage switching in gold atomic wire junctions

“…In the past two decades, the formation, evolution, and breaking of gold atomic chains that bridge a pair of electrodes have been the subject of many experimental and theoretical studies, motivated by their fundamental scientific interest and potential applications as the narrowest possible conducting wires for nanoscale electronic devices [1][2][3][4][5][6][7][8][9][10]. The electric current through such atomic chains can be measured in scanning tunneling microscopy experiments [11,12].…”

“…The conductance properties of gold atomic chains have also been investigated theoretically by means of extended Hückel theory [4], classical molecular dynamics simulations combined with a tight-binding approximation [7], and ab initio calculations [5,[8][9][10]. It was shown that the conductance of gold atomic wires is close to 1g 0 = 2e 2 /h for wires with different lengths [4,5].…”