Lattice Energetics and Correlation-Driven Metal-Insulator Transitions: The Case of 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>RuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Han, Qiang; Millis, Andrew J.

doi:10.1103/physrevlett.121.067601

Cited by 48 publications

(40 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Earlier dynamical mean field theory (DMFT) calculations of the MIT in Ca 2 RuO 4 predict that the full d xy orbital polarization with n xy ≈ 2, n xz ≈ n yz ≈ 1 and p = n xy − ( n xz + n yz )/2 ≈ 1 observed in the insulating state vanishes in the metallic L-Pbca phase 4,7,14,16,38,39 . This is qualitatively consistent with our experiments showing signatures of all three t 2 g orbitals on the Fermi surface.…”

Section: Resultsmentioning

confidence: 98%

“…Mott 2 , realistic numerical studies point to a far more important role of structural changes in stabilizing the Mott state of archetypal insulators 3,4 . This, together with recent theoretical advances, has led to renewed interest in the interplay of lattice energetics and electronic properties near Mott transitions 5–7 . Hydrostatic and uniaxial pressure is particularly important in the experimental study of Mott transitions and also has a profound effect on other emerging properties of quantum materials 1,8–12 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

In situ strain tuning of the metal-insulator-transition of Ca2RuO4 in angle-resolved photoemission experiments

et al. 2018

View full text Add to dashboard Cite

Pressure plays a key role in the study of quantum materials. Its application in angle resolved photoemission (ARPES) studies, however, has so far been limited. Here, we report the evolution of the k-space electronic structure of bulk Ca2RuO4, lightly doped with Pr, under uniaxial strain. Using ultrathin plate-like crystals, we achieve uniaxial strain levels up to −4.1%, sufficient to suppress the insulating Mott phase and access the previously unexplored electronic structure of the metallic state at low temperature. ARPES experiments performed while tuning the uniaxial strain reveal that metallicity emerges from a marked redistribution of charge within the Ru t2g shell, accompanied by a sudden collapse of the spectral weight in the lower Hubbard band and the emergence of a well-defined Fermi surface which is devoid of pseudogaps. Our results highlight the profound roles of lattice energetics and of the multiorbital nature of Ca2RuO4 in this archetypal Mott transition and open new perspectives for spectroscopic measurements.

show abstract

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

In situ strain tuning of the metal-insulator-transition of Ca2RuO4 in angle-resolved photoemission experiments

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Some first-principles studies on strongly correlated oxides have highlighted the important effect structural disorder/defects may have on the energy barriers between different magnetic states. 20,21 Similarly, a recent study demonstrated that structural distortions associated with replacing V with Cr are responsible for enhanced correlation effects and stabilizing an insulating state at high temperatures. 22 It was also shown that despite Cr and V having different number of electrons such a replacement does not result in charge doping.…”

Section: A General Considerationsmentioning

confidence: 98%

Role of defects in the metal-insulator transition in VO2 and V2O3

2019

View full text Add to dashboard Cite

The vanadates VO2 and V2O3 are prototypical examples of strongly correlated materials that exhibit a metal-insulator transition. While the phase transitions in these materials have been studied extensively, there is a limited understanding of how the properties of these materials are affected by the presence of defects and doping. In this study we investigate the impact of native point defects in the form of Frenkel defects on the structural, magnetic and electronic properties of VO2 and V2O3, using first-principles calculations. In VO2 the vanadium Frenkel pairs lead to a nontrivial insulating state. The unpaired vanadium interstitial bonds to a single dimer, which leads to a trimer that has one singlet state and one localized single-electron S = 1/2 state. The unpaired broken dimer created by the vanadium vacancy also has a localized S = 1/2 state. Thus, the insulating state is created by the singlet dimers, the trimer and the two localized S = 1/2 states. Oxygen Frenkel pairs, on the other hand, lead to a metallic state in VO2, but are expected to be present in much lower concentrations. In contrast, the Frenkel defects in V2O3 do not directly suppress the insulating character of the material. However, the disorder created by defects in V2O3 alters the local magnetic moments and in turn reduces the energy cost of a transition between the insulating and conducting phases of the material. We also find self-trapped small polarons in V2O3, which has implications for transport properties in the insulating phase.

show abstract

“…All −43.9 202.2 −0.25 0.4 All −44.6 205.1 −0.25 2.2 > 170 −43.0 199.7 −0.25 4.4 > 190 −43.5 200.7 −0.25 TABLE I. Variable Range Hopping regime fitting parameters b. Crystallographic axes vs RuO distances By means of DFT+U calculations, A. Millis and coworkers32 found a transformation matrix relating the variations of the crystallographic axis δa, δb and δc to the variations of the Ru − O distances in the RuO 6 octahedra, that is, δx, δy and δz:…”

mentioning

confidence: 99%

Emergence of a metallic metastable phase induced by electrical current in Ca2RuO4

et al. 2019

View full text Add to dashboard Cite

A comprehensive study of the behavior of the Mott insulator Ca2RuO4 under electrical current drive is performed by combining two experimental probes: the macroscopic electrical transport and the microscopic X-Ray diffraction. The resistivity, ρ, vs electric current density, J, and temperature, T , ρ(J,T), resistivity map is drawn. In particular, the meta-stable state, induced between the insulating and the metallic thermodynamic states by current biasing Ca2RuO4 single crystals, is investigated. Such an analysis, combined with the study of the resulting RuO6 octahedra energy levels, reveals that a metallic crystal phase emerges in the meta-stable regime. The peculiar properties of such a phase, coexisting with the well-established orthorhombic insulating and tetragonal metallic phases, allow to explain some of the unconventional and puzzling behaviors observed in the experiments, as a negative differential resistivity. arXiv:1912.01690v1 [cond-mat.str-el]

show abstract

Lattice Energetics and Correlation-Driven Metal-Insulator Transitions: The Case of Ca2RuO4

Cited by 48 publications

References 48 publications

In situ strain tuning of the metal-insulator-transition of Ca2RuO4 in angle-resolved photoemission experiments

In situ strain tuning of the metal-insulator-transition of Ca2RuO4 in angle-resolved photoemission experiments

Role of defects in the metal-insulator transition in VO2 and V2O3

Emergence of a metallic metastable phase induced by electrical current in Ca2RuO4

Contact Info

Product

Resources

About