Mott Transitions

Gabriel Kotliar

E. A. Szwed, Brian Vermilyea, D. J. Choksy +5 more

For a neutral system of positive and negative charges, such as atoms in a crystal, increasing the density causes the Mott transition from bound electrons to free electrons. The density of optically generated electron-hole systems can be controlled in situ by the power of optical excitation that enables the Mott transition from excitons, the bound pairs of electrons and holes, to free electrons and holes with increasing density. These Mott transitions occur in systems of pairs of the same kind, such as atoms or excitons. However, a different type of the Mott transition can occur for Bose polarons. A Bose polaron is a mobile particle of one kind in a Bose gas of particles of another kind. For the Mott transition in polarons, the polaron states vanish with increasing density of the surrounding gas. In this paper, we present the observation of this type of the Mott transition and the measurement of the Mott transition parameter $n_{\rm M}^{1/2} a_{\rm B}$ in 2D excitonic Bose polarons.

Yuekun Niu, Yu 煜 Ni 倪, Jianli Wang +4 more

Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points.

Walter Kohn

Masanori Kohno

Spectral properties of the two-dimensional Hubbard model near the Mott transition are investigated by using cluster perturbation theory. The Mott transition is characterized by freezing of the charge degrees of freedom in a single-particle excitation that leads continuously to the magnetic excitation of the Mott insulator. Various anomalous spectral features observed in cuprate high-temperature superconductors are explained in a unified manner as properties near the Mott transition.

Sindhunil Barman Roy