First-Order Isostructural Mott Transition in Highly Compressed MnO

Yoo, Choong‐Shik; Maddox, Brian; Klepeis, J.-H. P.; Iota, V.; Evans, W. J.; McMahan, A. K.; Hu, Michael Y.; Chow, Paul; Somayazulu, Maddury; Häusermann, Daniel M.; Scalettar, R. T.; Pickett, Warren E.

doi:10.1103/physrevlett.94.115502

Cited by 111 publications

(113 citation statements)

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“…We claim that the origin of the behavior of VO is related to the tendency of the d electrons to form local spin moments in the vicinity of a metal-insulator transition. From the insulating side, this transition has been recently observed in MnO under hydrostatic pressure 29 which changes the U / W ratio, keeping the number of electrons constant. Our data on VO shed light on the behavior of the metallic side approaching the localized limit upon doping.…”

Section: Resultsmentioning

confidence: 99%

VO: A strongly correlated metal close to a Mott-Hubbard transition

et al. 2007

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Here, we present experimental and computational evidences to support that rocksalt cubic VO is a strongly correlated metal with non-Fermi-liquid thermodynamics and an unusually strong spin-lattice coupling. An unexpected change of sign of metallic thermopower with composition is tentatively ascribed to the presence of a pseudogap in the density of states. These properties are discussed as signatures of the proximity to a magnetic quantum phase transition. The results are summarized in an electronic phase diagram for the 3d monoxides, which resembles that of other strongly correlated systems. The structural and electronic simplicity of 3d monoxides makes them ideal candidates to progress in the understanding of highly correlated electron systems.

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Section: Resultsmentioning

confidence: 99%

VO: A strongly correlated metal close to a Mott-Hubbard transition

et al. 2007

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“…This is the case with the observed metallic luster in the successive measurements of the same material MnO [10][11][12]. Therefore, below the critical point f d the reflectivity decreases sharply due to the transmission of the infinite dielectric cluster and specific plasmons passing through the connected system of tunnels in the metal.…”

mentioning

confidence: 81%

“…Under pressure due to different compressibility, a composite irreversibly can undergo both transitions. To illustrate this, we show a noncomposite example of the phase separation in the Mott insulator MnO [10][11][12]. It demonstrates both the resistance drop near 90 GPa and the subsequent reflectance sharp increase, which becomes pressure-independent at 127 GPa [13].…”

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Second Critical Point in First Order Metal-Insulator Transitions

Kostadinov

Patton

2008

Phys. Rev. Lett.

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For first order metal-insulator transitions we show that, together with the dc conductance zero, there is a second critical point where the dielectric constant becomes zero and further turns negative. At this point the metallic reflectivity sharply increases. The two points can be separated by a phase separation state in a 3D disordered system but may tend to merge in 2D. For illustration we evaluate the dielectric function in a simple effective medium approximation and show that at the second point it turns negative. We reproduce the experimental data on a typical Mott insulator such as MnO, demonstrating the presence of the two points clearly. We discuss other experiments for studies of the phase separation state and a similar phase separation in superconductors with insulating inclusions. DOI: 10.1103/PhysRevLett.101.226407 PACS numbers: 71.30.+h, 71.55.Jv, 74.25.Dw, 78.67.Àn The charge transport and metal-insulator transitions (MITs) in disordered systems have been discussed in many papers [1][2][3], reviews [4,5], and books [6][7][8][9]. The initial discussion resulted in agreement that at T ¼ 0 the transition is completely described by the dc conduction as a function of the Fermi level at T ¼ 0. This is true for second order MITs, where simultaneously with the vanishing of the conductance the real part of the dielectric function also vanishes. It is negative in the metallic state and positive in the dielectric one, and there is no phase separation in this case. Here we show that in a first order MIT in composites the dc conduction is not enough and the dc dielectric constant has to be considered in order to make the description complete. We will show that in a first order MIT in the composites, in disordered thermodynamically metastable 3D systems, there can be an intermediate two phase region separating the metallic state from the dielectric one, both at T ¼ 0 and at finite temperatures. We will consider such a metal-dielectric composite with a metallic volume fraction f, but our results are relevant for other first order MITs in homogeneous systems, due to the nucleation of metallic inclusions in the dielectric matrix under pressure, for example. In a composite, grains of both components are always present for any metallic volume fraction f Þ 0 and f Þ 1, and the resistance drop occurs at a volume fraction f c different from the dielectric function sign change f d and in different samples made with different metallic volume fractions. Under pressure due to different compressibility, a composite irreversibly can undergo both transitions. To illustrate this, we show a noncomposite example of the phase separation in the Mott insulator . It demonstrates both the resistance drop near 90 GPa and the subsequent reflectance sharp increase, which becomes pressure-independent at 127 GPa [13]. The data from Ref. [12] are given in Fig. 1, and a detailed discussion of MITs in MnO is given in [14].Specific phase separation state.-A metallic 3D sample is screening any static electric fields as well as the electrone...

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Spectroscopic Studies on the Metal–Insulator Transition Mechanism in Correlated Materials

et al. 2018

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The metal-insulator transition (MIT) in correlated materials is a novel phenomenon that accompanies a large change in resistivity, often many orders of magnitude. It is important in its own right but its switching behavior in resistivity can be useful for device applications. From the material physics point of view, the starting point of the research on the MIT should be to understand the microscopic mechanism. Here, an overview of recent efforts to unravel the microscopic mechanisms for various types of MITs in correlated materials is provided. Research has focused on transition metal oxides (TMOs), but transition metal chalcogenides have also been studied. Along the way, a new class of MIT materials is discovered, the so-called relativistic Mott insulators in 5d TMOs. Distortions in the MO (M = transition metal) octahedron are found to have a large and peculiar effect on the band structure in an orbital dependent way, possibly paving a way to the orbital selective Mott transition. In the final section, the character of the materials suitable for applications is summarized, followed by a brief discussion of some of the efforts to control MITs in correlated materials, including a dynamical approach using light.

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First-Order Isostructural Mott Transition in Highly Compressed MnO

Cited by 111 publications

References 21 publications

VO: A strongly correlated metal close to a Mott-Hubbard transition

VO: A strongly correlated metal close to a Mott-Hubbard transition

Second Critical Point in First Order Metal-Insulator Transitions

Spectroscopic Studies on the Metal–Insulator Transition Mechanism in Correlated Materials

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