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Möbius molecules and fragile Mott insulators
- Source :
- Physical Review B. 90
- Publication Year :
- 2014
- Publisher :
- American Physical Society (APS), 2014.
-
Abstract
- Motivated by the concept of M\"obius aromatics in organic chemistry, we extend the recently introduced concept of fragile Mott insulators (FMI) to ring-shaped molecules with repulsive Hubbard interactions threaded by a half-quantum of magnetic flux ($hc/2e$). In this context, a FMI is the insulating ground state of a finite-size molecule that cannot be adiabatically connected to a single Slater determinant, i.e., to a band insulator, provided that time-reversal and lattice translation symmetries are preserved. Based on exact numerical diagonalization for finite Hubbard interaction strength $U$ and existing Bethe-ansatz studies of the one-dimensional Hubbard model in the large-$U$ limit, we establish a duality between Hubbard molecules with $4n$ and $4n+2$ sites, with $n$ integer. A molecule with $4n$ sites is an FMI in the absence of flux but becomes a band insulator in the presence of a half-quantum of flux, while a molecule with $4n+2$ sites is a band insulator in the absence of flux but becomes an FMI in the presence of a half-quantum of flux. Including next-nearest-neighbor-hoppings gives rise to new FMI states that belong to multidimensional irreducible representations of the molecular point group, giving rise to a rich phase diagram.
- Subjects :
- Condensed Matter::Quantum Gases
Physics
Condensed Matter - Strongly Correlated Electrons
Hubbard model
Condensed matter physics
Mott insulator
Molecule
Condensed Matter::Strongly Correlated Electrons
Strongly correlated material
Electronic structure
Condensed Matter Physics
Kinetic energy
Electronic, Optical and Magnetic Materials
Subjects
Details
- ISSN :
- 1550235X and 10980121
- Volume :
- 90
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi.dedup.....6fac717cd90ea2bb27e8aac0512a646e