  An experimental determination of electronic phase diagrams of high-transition
temperature (high-$T_c$) superconductors forms the basis for a microscopic
understanding of unconventional superconductivity. For most high-$T_c$
superconductors, the electronic phase diagrams are established through partial
chemical substitution, which also induces lattice disorder. Here we show that
symmetry-specific uniaxial strain can be used to study electronic phases in
iron-based superconductors, composed of two-dimensional nearly square iron
lattice planed separated by other elements. By applying tunable uniaxial strain
along different high symmetry directions and carrying out transport
measurements, we establish strain-tuning dependent electronic nematicity,
antiferromagnetic (AF) order, and superconductivity of
BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$ superconductor. We find that uniaxial strain
along the nearest Fe-Fe direction can dramatically tune the AF order and
superconductivity, producing an electronic phase diagram clearly different from
the chemical substitution-induced one. Our results thus establish strain tuning
as a way to study the intertwined orders in correlated electron materials
without using chemical substitution.
