Physics and Astronomy Colloquium

I will discuss transport of electrons through quantum wires--nanoscale conductors in which the electrons are confined to one spatial dimension. Theory and experiments agree that the resistance of a quantum wire takes a universal value of h/2e2, where h is the Planck's constant, and e is the electron charge. However, a number of recent experiments show that in the regime of very low density of electrons in the wire the resistance increases by 40-100%. At such low densities the electrons repel each other very strongly, and may form a crystalline structure (Wigner crystal). In this regime the spins of electrons are nearly decoupled from each other, and the propagation of the spin excitations through the wire is impeded. I will argue that this effect should result in doubling of the resistance of the wire.