Mott transition

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

Monte Carlo simulation of the tight-binding model of graphene with partially screened Coulomb interactions

Abstract: We report on hybrid Monte Carlo simulations of the tight-binding model with long-range Coulomb interactions for the electronic properties of graphene. We investigate the spontaneous breaking of sublattice symmetry corresponding to a transition from the semimetal to an antiferromagnetic insulating phase. Our short-range interactions thereby include the partial screening due to electrons in higher energy states from ab initio calculations based on the constrained random phase approximation [T. O. Wehling et al., Phys. Rev. Lett. 106, 236805 (2011)]. In contrast to a similar previous Monte Carlo study [M. V. Ulybyshev et al., Phys. Rev. Lett. 111, 056801 (2013)], we also include a phenomenological model that describes the transition to the unscreened bare Coulomb interactions of graphene at half-filling in the long-wavelength limit. Our results show, however, that the critical coupling for the antiferromagnetic Mott transition is largely insensitive to the strength of these long-range Coulomb tails. They hence confirm the prediction that suspended graphene remains in the semimetal phase when a realistic static screening of the Coulomb interactions is included.

Effect of a magnetic field on Mott-Hubbard systems.

Abstract: The effect of a magnetic field on Mott-Hubbard systems is investigated by studying the half-filled Hubbard model in the limit of infinite dimensions. A first-order metamagnetic transition between the strongly correlated metal and the Mott insulator is found for a critical value of the applied field. The field and temperature dependence of the magnetization, one-particle properties, and susceptibility are studied and compared to the Gutzwiller approximation. The experimental relevance for transition-metal oxides and liquid $^{3}\mathrm{He}$ is discussed.

Mott physics and collective modes: An atomic approximation of the four-particle irreducible functional

Abstract: We discuss a generalization of the dynamical mean field theory (DMFT) for strongly correlated systems close to a Mott transition based on a systematic approximation of the fully irreducible four-point vertex. It is an atomic-limit approximation of a functional of the one- and two-particle Green functions, built with the second Legendre transform of the free energy with respect to the two-particle Green function. This functional is represented diagrammatically by four-particle irreducible (4PI) diagrams. Like the dynamical vertex approximation $(\mathrm{D}\mathrm{\ensuremath{\Gamma}}\mathrm{A})$, the fully irreducible vertex is computed from a quantum impurity model whose bath is self-consistently determined by solving the parquet equations. However, in contrast with $\mathrm{D}\mathrm{\ensuremath{\Gamma}}\mathrm{A}$ and DMFT, the interaction term of the impurity model is also self-consistently determined. The method interpolates between the parquet approximation at weak coupling and the atomic limit, where it is exact. It is applicable to systems with short-range and long-range interactions.

Superconductivity in the americium metal as a function of pressure: probing the Mott transition.

Abstract: High-pressure measurements of the resistivity of americium metal are reported to 27 GPa and down to temperatures of 0.4 K. The unusual dependence of the superconducting temperature (T(c)) on pressure is deduced. The critical field [H(c)(0) extrapolated to T=0] increases dramatically from 0.05 to approximately 1 T as the pressure is increased, suggesting that the type of superconductivity is changing as pressure increases. At pressures of approximately 16 GPa the 5f electrons of Am are changing from localized to itinerant, and the crystal structure also transforms to a complex one. The role of a Mott-type transition in the development of the peak in T(c) above 16 GPa is postulated.

Spectral Evolution in ( C a , S r ) RuO 3 near the Mott-Hubbard Transition

Abstract: We investigated optical properties of (Ca,Sr)RuO {sub 3} films on the borderline of a metal-insulator transition. Our results show all of the predicted characteristics for a metallic Mott-Hubbard system, including (i) a mass enhancement in dc limit, (ii) a U/2 excitation, and (iii) a U excitation. Also, self-consistency is exploited within the Gutzwiller-Brinkman-Rice picture for the Mott transition. Our finding displays that electron correlation should be important even in 4d materials. However, low frequency behaviors of electrodynamic quantities suggest extra scattering mechanisms in addition to the Mott-Hubbard correlation. {copyright} {ital 1999} {ital The American Physical Society }