0.4 and 0.7 conductance anomalies in quantum point contacts

Self-consistent modelling based on local spin-density formalism is employed to calculate conductance of quantum point contacts at finite temperatures. The total electrostatic potential exhibits spin-dependent splitting, which persists at temperatures up to 0.5 K and gives rise to the anomalies at 0.4 and 0.7 of the conductance quantum $2e^2/h$ occurring simultaneously in the absence of external magnetic fields.