Spontaneous particle-hole symmetry breaking of correlated fermions on the Lieb lattice
| Autor: | Fakher F. Assaad, Thomas C. Lang, M. Bercx, Johannes Hofmann |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Physics
Strongly Correlated Electrons (cond-mat.str-el) Condensed matter physics Quantum Monte Carlo FOS: Physical sciences Zero-point energy 02 engineering and technology Fermion Electron 021001 nanoscience & nanotechnology 01 natural sciences Condensed Matter - Strongly Correlated Electrons Quantum mechanics 0103 physical sciences Ising model Symmetry breaking 010306 general physics 0210 nano-technology Electronic band structure Charge density wave |
| Zdroj: | Physical Review B. 95 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | We study spinless fermions with nearest-neighbor repulsive interactions ($t$-$V$ model) on the two-dimensional three-band Lieb lattice. At half-filling, the free electronic band structure consists of a flat band at zero energy and a single cone with linear dispersion. The flat band is expected to be unstable upon inclusion of electronic correlations, and a natural channel is charge order. However, due to the three-orbital unit cell, commensurate charge order implies an imbalance of electron and hole densities and therefore doping away from half-filling. Our numerical results show that below a finite-temperature Ising transition a charge density wave with one electron and two holes per unit cell and its partner under particle-hole transformation are spontaneously generated. Our calculations are based on recent advances in auxiliary-field and continuous-time quantum Monte Carlo simulations that allow sign-free simulations of spinless fermions at half-filling. It is argued that particle-hole symmetry breaking provides a route to access levels of finite doping, without introducing a sign problem. 9 pages, 6 figures, added data for strong Coulomb repulsion and classical Ising-limit |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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