Mott transition

About: Mott transition is a research topic. Over the lifetime, 2444 publications have been published within this topic receiving 78401 citations.

Direct observation of melted Mott state evidenced from Raman scattering in 1T-TaS 2 single crystal

Abstract: The evolution of electron correlation and charge density wave (CDW) in 1T-TaS2 single crystal has been investigated by temperature-dependent Raman scattering, which undergoes two obvious peaks of A 1g modes about 70.8 cm−1 and 78.7 cm−1 at 80 K, respectively. The former peak at 70.8 cm−1 is accordant with the lower Hubbard band, resulting in the electron-correlation-driven Mott transition. Strikingly, the latter peak at 78.7 cm−1 shifts toward low energy with increasing the temperature, demonstrating the occurrence of nearly commensurate CDW phase (melted Mott phase). In this case, phonon transmission could be strongly coupled to commensurate CDW lattice via Coulomb interaction, which likely induces appearance of hexagonal domains suspended in an interdomain phase, composing the melted Mott phase characterized by a shallow electron pocket. Combining electronic structure, atomic structure, transport properties with Raman scattering, these findings provide a novel dimension in understanding the relationship between electronic correlation, charge order, and phonon dynamics.

Conversion of an electron-hole plasma into a high density excitonic state in ZnO epitaxial thin films

Abstract: Time-resolved luminescence spectra of an exciton-exciton scattering process and an electron–hole plasma (EHP) were measured in ZnO epitaxial thin films by the optical Kerr gate method. At moderate excitation density below critical Mott density, stimulated emission of luminescence due to the exciton–exciton scattering process (P band) was observed. The P band shows a red shift and spectral narrowing in the first 1–2 ps after the excitation which reflects a thermal redistribution of excitons in the n = 1 excitonic state. On the other hand, at high excitation density above the critical Mott density, stimulated emission of the luminescence due to the EHP was observed. After thermalization of the EHP, the luminescence intensity of the EHP band decreases with time, and the EHP band converts to the P band after ∼10 ps through a reverse Mott transition. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Model Hamiltonians and First Principles Electronic Structure Calculations

Abstract: We review the basic ideas of the dynamical mean field theory (DMFT). Some of the remarkable insights into the electronic structure of strongly correlated electrons are introduced using the simplest model Hamiltonians. We then discuss the perspectives for carrying out more realistic DMFT studies of strongly correlated electron systems and we compare it with existent methods, LDA and LDA+U. We stress the existence of new functional for electronic structure calculations which allow us to treat situations where the single-particle description breaks down such as the vicinity of the Mott transition.

Simulating heavy fermion physics in optical lattice: Periodic Anderson model with harmonic trapping potential

Abstract: The periodic Anderson model (PAM), where local electron orbitals interplay with itinerant electronic carriers, plays an essential role in our understanding of heavy fermion materials. Motivated by recent proposals for simulating the Kondo lattice model (KLM) in terms of alkaline-earth metal atoms, we take another step toward the simulation of PAM, which includes the crucial charge/valence fluctuation of local f-electrons beyond purely low-energy spin fluctuation in the KLM. To realize PAM, a transition induced by a suitable laser between the electronic excited and ground state of alkaline-earth metal atoms (1 S 0⇌3 P 0) is introduced. This leads to effective hybridization between local electrons and conduction electrons in PAM. Generally, the SU(N) version of PAM can be realized by our proposal, which gives a unique opportunity to detect large-N physics without complexity in realistic materials. In the present work, high-temperature physical features of standard [SU(2)] PAM with harmonic trapping potential are analyzed by quantum Monte Carlo and dynamic mean-field theory, where the Mott/orbital-selective Mott state was found to coexist with metallic states. Indications for near-future experiments are provided. We expect our theoretical proposal and (hopefully) forthcoming experiments will deepen our understanding of heavy fermion systems. At the same time, we hope these will trigger further studies on related Mott physics, quantum criticality, and non-trivial topology in both the inhomogeneous and nonequilibrium realms.