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Charge dynamics of the antiferromagnetically ordered Mott insulator
- Source :
- New Journal of Physics. 18:103004
- Publication Year :
- 2016
- Publisher :
- IOP Publishing, 2016.
-
Abstract
- We introduce a slave-fermion formulation in which to study the charge dynamics of the half-filled Hubbard model on the square lattice. In this description, the charge degrees of freedom are represented by fermionic holons and doublons and the Mott-insulating characteristics of the ground state are the consequence of holon–doublon bound-state formation. The bosonic spin degrees of freedom are described by the antiferromagnetic Heisenberg model, yielding long-ranged (Neel) magnetic order at zero temperature. Within this framework and in the self-consistent Born approximation, we perform systematic calculations of the average double occupancy, the electronic density of states, the spectral function and the optical conductivity. Qualitatively, our method reproduces the lower and upper Hubbard bands, the spectral-weight transfer into a coherent quasiparticle band at their lower edges and the renormalisation of the Mott gap, which is associated with holon–doublon binding, due to the interactions of both quasiparticle species with the magnons. The zeros of the Green function at the chemical potential give the Luttinger volume, the poles of the self-energy reflect the underlying quasiparticle dispersion with a spin-renormalised hopping parameter and the optical gap is directly related to the Mott gap. Quantitatively, the square-lattice Hubbard model is one of the best-characterised problems in correlated condensed matter and many numerical calculations, all with different strengths and weaknesses, exist with which to benchmark our approach. From the semi-quantitative accuracy of our results for all but the weakest interaction strengths, we conclude that a self-consistent treatment of the spin-fluctuation effects on the charge degrees of freedom captures all the essential physics of the antiferromagnetic Mott–Hubbard insulator. We remark in addition that an analytical approximation with these properties serves a vital function in developing a full understanding of the fundamental physics of the Mott state, both in the antiferromagnetic insulator and at finite temperatures and dopings.
- Subjects :
- Condensed Matter::Quantum Gases
Physics
Strongly Correlated Electrons (cond-mat.str-el)
Condensed matter physics
Hubbard model
Heisenberg model
Magnon
Mott insulator
FOS: Physical sciences
General Physics and Astronomy
02 engineering and technology
021001 nanoscience & nanotechnology
01 natural sciences
Optical conductivity
Condensed Matter - Strongly Correlated Electrons
0103 physical sciences
Quasiparticle
Antiferromagnetism
Condensed Matter::Strongly Correlated Electrons
010306 general physics
0210 nano-technology
Ground state
Subjects
Details
- ISSN :
- 13672630
- Volume :
- 18
- Database :
- OpenAIRE
- Journal :
- New Journal of Physics
- Accession number :
- edsair.doi.dedup.....2c1763132b6a7a4c5aa770a1e0ac9636