Double-Layer Systems at Zero Magnetic Field

摘要: We investigate theoretically the effects of intralayer and interlayer exchange in biased double-layer electron hole systems, absence a magnetic field. use variational Hartree-Fock-like approximation to analyze layer separation, density, tunneling, applied gate voltages on densities phase coherence. In agreement with earlier work, we find that for very small separations low densities, an interlayer-correlated ground state possessing spontaneous coherence (SILC) is obtained, even tunneling. contrast as function total there exist four, rather than three, distinct noncrystalline phases balanced systems without The newly identified exists narrow range has three components slightly unequal one being spin polarized, other unpolarized. An additional two-component also possible presence sufficiently strong bias or lowest-density SILC fully spin- pseudospin-polarized ``one-component'' discussed by Zheng {\it et al.} [Phys. Rev. B {\bf 55}, 4506 (1997)]. argue this will produce finite Coulomb drag at zero temperature due SILC. calculate particle each voltage can reduce prevent abrupt transfers charge between two layers. effect capacitance.