Suguru Ueda, Norio Kawakami, Manfred Sigrist
We present a theoretical study of a model heterostructure for a
Mott-insulator sandwiched between two band insulators, such as SrTiO3/LaTiO3.
Particular emphasis is given on the interplay between magnetism and
inhomogeneous charge distributions. Our mean-field analysis of the generalized
Hubbard model displays numerous ordered phases in the ground-state phase
diagram. In particular, we find a canted antiferromagnetic state near the
interface when antiferromagnetic-ordering exists inside the Mott insulator. A
checkerboard charge-ordering proposed previously is also stabilized for large
long-range Coulomb interactions. Regarding its origin we also point out the
importance of interlayer spin-mediated interactions. It is further shown that
such a strong spin-charge coupling gives rise to pronounced magnetic/charge
order phase transitions in external magnetic fields: a firstorder metamagnetic
transition and a reentrant charge-order transition with checkerboard pattern.
The mechanisms stabilizing these intriguing phases are explored through a
detailed analysis of the physical quantities with special focus on the
spin-charge interplay.
View original:
http://arxiv.org/abs/1202.5423
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