Itinerant ferromagnetism of repulsive two-component Fermi gas in the triple-well traps

Abstract

Based on Thomas-Fermi density functional theory, itinerant ferromagnetism of repulsive two-component Fermi gas trapped in a triple-well is studied. The density profiles of the two components are calculated in three types of triple-well trapping potential. The conclusion is drawn that phase separation relates closely not only to the interaction strength, but also to the shape of the trapping potential, which plays a critical role in determining the density profile of the gas. The separation in each type of trapping potential is a result of the competition between repulsive interaction energy and the kinetic energy. Numerical results show that phase separation occurs once the coupling constant reaches a critical value. With further increase in the coupling constant, the interplay between wells is enhanced, which may cause complex separation. Despite our crude treatment in the Thomas-Fermi approximation, the results may help to explore and understand the nature of itinerant ferromagnetism of trapped Fermi mixtures in both theoretical and experimental research in the future.