Charge density wave in single-layer Pb/Ge(111) driven by Pb-substrate exchange interaction

Abstract

Single layer Pb on top of (111) surfaces of group IV semiconductors hosts charge density wave and superconductivity depending on the coverage and on the substrate. These systems are normally considered to be experimental realizations of single band Hubbard models and their properties are mostly investigated using lattice models with frozen structural degrees of freedom, although the reliability of this approximation is unclear. Here, we consider the case of Pb/Ge(111) at 1/3 coverage, for which surface X-ray diffraction and ARPES data are available. By performing first principles calculations, we demonstrate that the non-local exchange between Pb and the substrate drives the system into a $3\times 3$ charge density wave. The electronic structure of this charge ordered phase is mainly determined by two effects: the magnitude of the Pb distortion and the large spin-orbit coupling. Finally, we show that the effect applies also to the $3\times 3$ phase of Pb/Si(111) where the Pb-substrate exchange interaction increases the bandwidth by more than a factor 1.5 with respect to DFT+U, in better agreement with STS data. The delicate interplay between substrate, structural and electronic degrees of freedom invalidates the widespread interpretation available in literature considering these compounds as physical realizations of single band Hubbard models.

To appear in Phys. Rev. B

References in corpus (21)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Long-range incommensurate charge fluctuations in (Y,Nd)Ba2Cu3O(6+x)
• Ubiquitous Interplay between Charge Ordering and High-Temperature Superconductivity in Cuprates
• Charge order driven by Fermi-arc instability in Bi2201
• Long-range Coulomb interactions in surface systems: a first principles description within self-consistently combined GW and dynamical mean field theory
• Triangular Mott-Hubbard Insulator Phases of Sn/Si(111) and Sn/Ge(111) Surfaces
• Phonon-assisted magnetic Mott-insulating state in the charge density wave phase of single-layer 1TNbSe2
• Charge ordering and correlation effects in the extended Hubbard model
• Realization of a hole-doped Mott insulator on a triangular silicon lattice
• Charge density wave and spin $1/2$ insulating state in single layer 1T-NbS${}_2$
• What about U on Surfaces? - Extended Hubbard Models for Adatom Systems from First Principles
• Non-local correlations in metals close to a charge order insulator transition
• Realistic modeling of the electronic structure and the effect of correlations for Sn/Si(111) and Sn/Ge(111) surfaces
• Unconventional superconductivity in the extended Hubbard model: Weak-coupling renormalization group
• Chiral spin texture in the charge-density-wave phase of the correlated metallic Pb/Si(111) monolayer
• d-wave superconductivity from electron-phonon interactions
• Spin-orbit coupling and magnetic interactions in Si(111):{C,Si,Sn,Pb}
• Correlation-driven charge order in a frustrated two-dimensional atom lattice
• Ferrimagnetic Slater Insulator Phase of the Sn/Ge(111) Surface
• Electronic correlation effects and Coulomb gap in the Si(111)-$(\sqrt{3}\times \sqrt{3})$-Sn surface

Cited by in corpus (3)

• Doping-dependent charge- and spin-density wave orderings in a monolayer of Pb adatoms on Si(111)
• Electronic structure, spin-orbit interaction and electron-phonon coupling of triangular adatom lattices on semiconductor substrates
• The electronic structure of a doped Mott-Hubbard surface