We demonstrate that at a filling of n=1.5, a hexatic insulating state obtains in the extended Hubbard model on a triangular lattice. Composed of two tetragonal sublattices with fillings of n=1 and n=2, the insulating state is charge ordered and possesses an antiferromagnetic superlattice with a dimension of a×3. Two distinct energy scales arise in our model: a charge gap for the insulator and the effective exchange interaction in the antiferromagnet. Our model is capable of explaining both qualitatively and quantitatively the Hall coefficient including the sign change, the temperature dependence of the resistivity, and the persistence of antiferromagnetism above the insulating state.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Feb 12 2007|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics