  We propose a microscopic physical mechanism that stabilizes coexistence of
the Kondo effect and antiferromagnetism in heavy-fermion systems. We consider a
two-dimensional quantum Kondo-Heisenberg lattice model and show that long-range
electron hopping leads to a robust antiferromagnetic Kondo state. By using a
modified slave-boson mean-field approach we analyze the stability of the heavy
antiferromagnetic phase across a range or parameters, and discuss transitions
between different phases. We also address connection to experiments on heavy
fermion compounds.
