Finite-temperature crossover and the quantum Widom line near the Mott transition

Vučičević, J.; Terletska, Hanna; Tanasković, D.; Dobrosavljević, V.

doi:10.1103/physrevb.88.075143

Cited by 101 publications

(141 citation statements)

References 66 publications

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“…We find that, for the doped Mott insulator, the resistivity shows very weak temperature dependence along the QWL. In particular, above T = 0.08 it follows the line of constant resistivity which coincides with the MIR limit, ρ * (T > 0.08) = ρ MIR (in contrast to the behavior previously established at halffilling [17,18] where ρ ρ MIR along the QWL). In fact, all curves converge precisely to the MIR limit at high temperatures, suggesting its fundamental role in characterizing the metal-insulator crossover for doped Mott insulators.…”

supporting

confidence: 43%

“…At the critical end-point (red dots) the two solutions merge, and above it no true distinction between the phases exists; only a rapid crossover is observed upon variation of U or µ. Previous work [17,18] examined the vicinity of the interaction-driven MIT at half-filling; here we analyze the broad finite temperature crossover region between the half-filled Mott insulator and the doped Fermi liquid state [27][28][29][30]. This "Bad Metal" regime, displaying very different transport behavior than that found at half-filling, is the main focus of this work.…”

mentioning

confidence: 94%

“…This can be achieved by focusing on the "maximally frustrated Hubbard model", where an exact solution can be obtained by solving Dynamical Mean-Field Theory (DMFT) equations [16] in the paramagnetic phase. Although various aspects of the DMFT equation have been studied for more than twenty years, only very recent work [17,18] established how to identify the quantum critical (QC) behavior associated with the interaction-driven Mott transition at half-filling.Here we present a large-scale computational study across the entire phase diagram, showing that qualitatively different transport behavior is found in doped Mott insulators. It reveals a clear and quantitative connection between BM phenomenology and the signatures of Mott quantum criticality, including the characteristic "mirror symmetry" [19] of the relevant scaling function.…”

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confidence: 99%

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Bad-Metal Behavior Reveals Mott Quantum Criticality in Doped Hubbard Models

et al. 2015

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Bad-Metal (BM) behavior featuring linear temperature dependence of the resistivity extending to well above the Mott-Ioffe-Regel (MIR) limit is often viewed as one of the key unresolved signatures of strong correlation. Here we associate the BM behavior with the Mott quantum criticality by examining a fully frustrated Hubbard model where all long-range magnetic orders are suppressed, and the Mott problem can be rigorously solved through Dynamical Mean-Field Theory. We show that for the doped Mott insulator regime, the coexistence dome and the associated first-order Mott metal-insulator transition are confined to extremely low temperatures, while clear signatures of Mott quantum criticality emerge across much of the phase diagram. Remarkable scaling behavior is identified for the entire family of resistivity curves, with a quantum critical region covering the entire BM regime, providing not only insight, but also quantitative understanding around the MIR limit, in agreement with the available experiments.PACS numbers: 71.27.+a,71.30.+h Metallic transport inconsistent with Fermi liquid theory has been observed in many different systems; it is often linked to quantum criticality around some ordering phase transition [1, 2]. Such behavior is notable near quantum critical points in good conductors, for example in heavy fermion compounds [3, 4]. In several other classes of materials, however, much more dramatic departures form conventional metallic behavior are clearly observed, where resistivity still rises linearly with temperature, but it reaches paradoxically large values, well past the MIR limit [5, 6]. This "Bad-Metal" (BM) behavior [7], was first identified in the heyday of high-temperature superconductivity, in materials such as La 2−x Sr x CuO 4 [8]. While the specific copper-oxide family and related high-T c materials remain ill-understood and marred with controversy, it soon became clear that BM behavior is a much more general feature [6] of materials close to the Mott metal-insulator transition (MIT) [9]. Indeed, it has been clearly identified also in various oxides [10, 11], organic Mott systems [12][13][14], as well as more recently discovered families of iron pnictides [15]. Despite years of speculation and debate, so far its clear physical interpretation has not been established.To gain reliable insight into the origin of BM behavior, it is useful to examine an exactly solvable model system, where one can suppress all possible effect associated with the approach to some broken symmetry phase, or those specific to low dimensions and a given lattice structure. This can be achieved by focusing on the "maximally frustrated Hubbard model", where an exact solution can be obtained by solving Dynamical Mean-Field Theory (DMFT) equations [16] in the paramagnetic phase. Although various aspects of the DMFT equation have been studied for more than twenty years, only very recent work [17,18] established how to identify the quantum critical (QC) behavior associated with the interaction-driven Mott transition at ...

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confidence: 43%

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confidence: 94%

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confidence: 99%

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Bad-Metal Behavior Reveals Mott Quantum Criticality in Doped Hubbard Models

et al. 2015

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“…At half-filling, extensive work has shown the first-order transition is analogous to the liquid-gas transition, placing the Mott transition within the Ising universality class [20][21][22][23][24][25][26][27] . In this work, we extend the construction away from half-filling into the µ-U plane 28 .…”

Section: Landau Free Energymentioning

confidence: 99%

“…In first-order transitions without an organizing symmetry, any number of fields can be chosen to construct the free energy 21,22,27 . The choice of the quantities conjugate to the physical tuning parameters µ and U allow for a transparent construction of the order parameter which can uniformly treat both the bandwidth and filling controlled transitions.…”

Section: Landau Free Energymentioning

confidence: 99%

Interfaces in coexisting metals and Mott insulators

Lee

Yee

2017

Phys. Rev. B

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Motivated by the direct observation of electronic phase separation in first-order Mott transitions, we model the interface between the thermodynamically coexisting metal and Mott insulator. We show how to model the required slab geometry and extract the electronic spectra. We construct an effective Landau free energy and compute the variation of its parameters across the phase diagram. Finally, using a linear mixture of the density and double-occupancy, we identify a natural Ising order parameter which unifies the treatment of the bandwidth and filling controlled Mott transitions.

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Percolation transition in two dimensional electron gas: A cellular automaton model

Najafi

2018

Solid State Communications

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A new type of disorder-driven electronic percolation transition is found for two-dimensional electron gas (2DEG), based on a quantum cellular automaton model. This transition is shown to be accompanied with a metal-insulator transition, as well as a singularity in the electronic compressibility. To this end, the electronic system which is assumed to be in contact with an electronic reservoir, is meshed by using of the phase coherence length ζ φ as an extent which divides the spatial dynamics of the electrons into two separate regimes and controls the localization of electrons. For the scales much smaller than ζ φ the treatment is quantum mechanical, whereas for the scales much larger than ζ φ the picture of semi-classical transport works and the classical Mote Carlo method is used. Thomas-Fermi-Dirac (TFD) theory is employed to find the dependence of the free energy of each cell on the temperature (T ), the (charged) disorder strength (∆) and the charge content of the cell, and a cellular automaton model for transporting the electrons between the cells is developed. At the transition line (in the T − ∆ space) the geometrical (e.g. correlation length) quantities also diverge and some power-law behaviors emerge with some critical exponents in agreement with the Gaussian free field (GFF) and the percolation theory. In the percolating side the spanning cluster probability (SCP) (as a realization of the conductivity) has a decreasing behavior in terms of the temperature which is the characteristics of the metallic phase. Our simple model yields the important features of the experimental observations, e.g. the singularity in the conductivity in some critical density and also the universality (non-universality) of the metal-insulator transition (MIT) for the small (large) disorders in 2DEG. A T − ∆ phase diagram of the electron gas is drawn in which along with the mentioned transition line, a zero-heat capacity line is also observed in which the system becomes unstable.

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Finite-temperature crossover and the quantum Widom line near the Mott transition

Cited by 101 publications

References 66 publications

Bad-Metal Behavior Reveals Mott Quantum Criticality in Doped Hubbard Models

Bad-Metal Behavior Reveals Mott Quantum Criticality in Doped Hubbard Models

Interfaces in coexisting metals and Mott insulators

Percolation transition in two dimensional electron gas: A cellular automaton model

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