  A new tetrahedral structure model was developed and the geometrical structure
of jammed disordered packings of monodisperse spheres with different friction
coefficients was systematically characterized. An intrinsic structure feature
is revealed for all jammed disordered packings, which is determined only by the
packing fraction, independent of interparticle friction. Moreover, the
structural configurations associated with crystal phases are more prevalent
than the geometric frustrated ones. In addition, irregular simplexes are found
to play a key role in an increase in density, rather than regular simplexes, in
contrast to previous expectation. Our model provides an intrinsic structural
basis for the random close packing.
