Orbital ordering in undoped manganites using Jahn-Teller interaction
Abstract
To understand the orbital ordering of
LaMn
O
3
in the ground state, we study it in the A-type spin antiferromagnetic state. We calculate the two-dimensional response functions associated with the Jahn-Teller
Q
2
and
Q
3
distortions and find that they diverge at the wavevector
π
,
π
). Furthermore, the
Q
2
response function diverges faster which indicates that perhaps the ordering of the orbitals at low temperatures is dominated by the
Q
2
distortion. We calculate the ground state energy for the cases when only one of the
Q
2
and
Q
3
modes is excited cooperatively and find that the
Q
2
excited state yields lower energy.