Can Correlations Drive a Band Insulator Metallic?

Garg, Arti; Krishnamurthy, H. R.; Randeria, Mohit

doi:10.1103/physrevlett.97.046403

Cited by 130 publications

(206 citation statements)

References 14 publications

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“…In order to demonstrate our argument, we describe the effects of ∆ using the ionic Hubbard model [13,14,15,16,17,18,19] on the 2D honeycomb lattice. We examine the system using the coherent-potential approximation (CPA) [20], which is equivalent to the "scattering correction" of the Hubbard III approximation [21].…”

Section: Introductionmentioning

confidence: 99%

Disappearance of the Dirac cone in silicene due to the presence of an electric field

Rowlands¹,

Zhang²

2014

Chinese Phys. B

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(Received X XX XXXX; revised manuscript received X XX XXXX) Using the two-dimensional ionic Hubbard model as a simple basis for describing the electronic structure of silicene in the presence of an electric field induced by the substrate, we use the coherent-potential approximation to calculate the zero-temperature phase diagram and associated spectral function at half filling. We find that any degree of symmetry-breaking induced by the electric field causes the silicene structure to lose its Dirac fermion characteristics, thus providing a simple mechanism for the disappearance of the Dirac cone.

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Section: Introductionmentioning

confidence: 99%

Disappearance of the Dirac cone in silicene due to the presence of an electric field

Rowlands¹,

Zhang²

2014

Chinese Phys. B

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“…Recently the evolution of a band insulator (BI) into a Mott insulator upon increasing the interaction strength has been studied in the context of the ionic Hubbard model, 5,6,7,8,9,10,11,12 a two-band Hubbard model with crystal-field splitting, 13 and a bilayer model with two identical Hubbard planes coupled by single-particle hopping. 14,15,16,17,18 Different scenarios have emerged with the possibility of an intervening phase and continuous or discontinuous transitions at critical interaction strengths.…”

Section: Introductionmentioning

confidence: 99%

Correlations in a band insulator

et al. 2009

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We study a model of a covalent band insulator with on-site Coulomb repulsion at half-filling using dynamical mean-field theory. Upon increasing the interaction strength the system undergoes a discontinuous transition from a correlated band insulator to a Mott insulator with hysteretic behavior at low temperatures. Increasing the temperature in the band insulator close to the insulator-insulator transition we find a crossover to a Mott insulator at elevated temperatures. Remarkably, correlations decrease the energy gap in the correlated band insulator. The gap renormalization can be traced to the low-frequency behavior of the self-energy, analogously to the quasiparticle renormalization in a Fermi liquid. While the uncorrelated band insulator is characterized by a single gap for both charge and spin excitations, the spin gap is smaller than the charge gap in the correlated system.

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“…Garg et al found [6] that for the IHM, treated within single site DMFT, the band gap becomes zero at a critical U c1 , with a Mott gap re-emerging at a larger U c2 . In between, the system is metallic.…”

mentioning

confidence: 99%

“…This bears a strong resemblance to the dispersion relation of the 2D IHM whose superlattice potential ∆ j (−1) j n j similarly has the effect of opening a band gap at q = (π, π), altering the ∆ = 0 dispersion relation ǫ q to E q = ± ǫ 2 q + ∆ 2 . Real space Quantum Monte Carlo (QMC) [8] has supplemented DMFT studies of the IHM [6] by allowing for magnetic order and concluded that U could cause the appearance of a metallic phase. However, despite the similarity in E q between the IHM and Eq.…”

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confidence: 99%

Magnetic transition in a correlated band insulator

et al. 2013

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The effect of on-site electron-electron repulsion U in a band insulator is explored for a bilayer Hubbard Hamiltonian with opposite sign hopping in the two sheets. The ground state phase diagram is determined at half-filling in the plane of U and the interplanar hybridization V through a computation of the antiferromagnetic (AF) structure factor, local moments, single particle and spin wave spectra, and spin correlations. Unlike the case of the ionic Hubbard model, no evidence is found for a metallic phase intervening between the Mott and band insulators. Instead, upon increase of U at large V , the behavior of the local moments and of single-particle spectra give quantitative evidence of a crossover to a Mott insulator state preceeding the onset of magnetic order. Our conclusions generalize those of single-site dynamical mean field theory, and show that including interlayer correlations results in an increase of the single particle gap with U .

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Can Correlations Drive a Band Insulator Metallic?

Cited by 130 publications

References 14 publications

Disappearance of the Dirac cone in silicene due to the presence of an electric field

Disappearance of the Dirac cone in silicene due to the presence of an electric field

Correlations in a band insulator

Magnetic transition in a correlated band insulator

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