  We report the existence of confined electronic states at the (110) and (111)
surfaces of SrTiO3. Using angle-resolved photoemission spectroscopy, we find
that the corresponding Fermi surfaces, subband masses, and orbital ordering are
different from the ones at the (001) surface of SrTiO3. This occurs because the
crystallographic symmetries of the surface and sub-surface planes, and the
electron effective masses along the confinement direction, influence the
symmetry of the electronic structure and the orbital ordering of the t2g
manifold. Remarkably, our analysis of the data also reveals that the carrier
concentration and thickness are similar for all three surface orientations,
despite their different polarities. The orientational tuning of the microscopic
properties of two-dimensional electron states at the surface of SrTiO3 echoes
the tailoring of macroscopic (e.g. transport) properties reported recently in
LaAlO3/SrTiO3 (110) and (111) interfaces, and is promising for searching new
types of 2D electronic states in correlated-electron oxides.
