Antiferro-orbital ordering

Fig. 8 Schematic phase diagram for the two-site E e system at half-filling in the g, J) space. AFO and SDW indicate, respectively, antiferro-orbital ordering and spin density wave states. The electronic state is specified by either the bare electron (Bare), the single-polaron (SP), or the bipolaron (BP). Parameters g, (Oo/t, and J/U are, respectively, chosen as 1, 1, 0.5 along the line 1...

The calculated quantities include charge density wave (CDW), spin density wave, antiferro-orbital ordering, and electron-pairing response functions. The corresponding operators are the density operator A , the spin density operator the antiferro-orbital operator A°, and the singlet pairing operator , all of which are defined in terms of the original orbitals of e(= and 9 = d 2, .2) as... 

Fig. 10 The normaUzed response functions for t = (Uo, g = (Uo, and J/U = 0.5. SCPO is the response of the singlet Cooper pairing with pseudospin zero (xP ), SCPl that of the singlet Cooper pairing with pseudospin one (/P ), AFO the antiferro-orbital ordering (x°), SDW (/ ), and CDW (x ). Note that the results for SCPO, SCPl, and CDW are given in ten times magnification...

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