  Using nonequilibrium molecular dynamics (NEMD) simulations, we study the
properties of supercooled liquids of Si under shear at T=1060K over a range of
densities encompassing the low-density liquid (LDL) and high-density liquid
(HDL) forms. This enables us to generate nonequilibrium steady-states of the
LDL and HDL polymorphs, that remain stabilized in their liquid forms for as
long as the shear is applied. This is unlike the LDL and HDL forms at rest,
which are metastable under those conditions and, when at rest, rapidly undergo
a transition towards the crystal, i.e. the thermodynamically stable equilibrium
phase. In particular, through a detailed analysis of the structural and
energetic features of the liquids under shear, we identify the range of
densities, as well as the range of shear rates, that give rise to the two
forms. We also show how the competition between shear and tetrahedral order
impacts the two-body entropy in steady-states of Si under shear. These results
open the door to new ways of utilizing shear to stabilize forms that are
metastable at rest and can exhibit unique properties, since, for instance,
experiments on Si have shown that HDL is metallic, with no band gap, while LDL
is semimetallic, with a pseudogap.
