Effects of electron interactions at crossings of Zeeman-split subbands in quantum wires

Recent experimental studies of Zeeman-split one-dimensional subbands in ballistic quantum wires in an in-plane magnetic field show that additional nonquantized conductance structures occur as subbands cross at low electron densities [A. C. Graham , Phys. Rev.Lett. 91, 136404 (2003)]. These structures are called 0.7 analogs. We analyze the experimental transconductance data within the Kohn-Sham spin-density-functional method, including exchange and correlation effects for an infinite split-gate quantum wire in a parallel, in-plane magnetic field B-parallel to. Energy levels are found to rearrange abruptly as they cross due to polarization effects driven by exchange and Coulomb interactions. Experimental qualitative features are explained well by this model.