Strong particle-hole asymmetry of charge instabilities in doped Mott insulators

Bejas, Matías; Greco, A.; Yamase, Hiroyuki

doi:10.1088/1367-2630/16/12/123002

Cited by 16 publications

(44 citation statements)

References 77 publications

(216 reference statements)

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“…At T = 10 −5 a very sharp peak forms at q = q 1 . This peak is due to the proximity to a quantum critical point of the d-wave bond-order instability, which is present at δ c ≈ 0.13 [21]. However, once the temperature is increased, the peak is immediately broadened and becomes less clear already at T = 0.01.…”

Section: Resultsmentioning

confidence: 94%

d -wave bond-order charge excitations in electron-doped cuprates

Yamase

Bejas

Greco

2015

EPL

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We study charge excitation spectra in the two-dimensional t-J model on a square lattice to explore a charge-order tendency recently found in electron-doped cuprates around the carrier density 0.15. The static susceptibility of dwave charge density, which corresponds to the nematic susceptibility at the momentum transfer q = (0, 0), shows two characteristic peaks at momenta of the form q1 = (q ′ , q ′ ) and q2 = (q, 0). These two peaks originate from the socalled 2kF scattering processes enhanced by the d-wave character of the bond-charge density. The peak at q1 is much broader, but develops to be very sharp in the vicinity of its instability, whereas the peak at q2 becomes sharper with decreasing temperature, but does not diverge. The equal-time correlation function, which is measured by resonant x-ray scattering, exhibits a momentum dependence similar to the static susceptibility. We also present energy-resolved charge excitation spectra. The spectra show a V-shaped structure around q = (0, 0) and bend back toward close to zero energy due to the charge-order tendency at q1 and q2. The resulting spectra form gap-like features with a maximal gap at q ≈ q1/2 and q2/2. We discuss implications for the recent experiments in electron-doped cuprates.

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Section: Resultsmentioning

confidence: 94%

d -wave bond-order charge excitations in electron-doped cuprates

Yamase

Bejas

Greco

2015

EPL

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“…4(b) and 6 in Ref. 26 for the phase diagram. As seen in the phase diagram, there are other CO tendencies close to d-wave bond-charge order and their low-energy charge excitations are actually present; see Fig.…”

Section: Model and Formalismmentioning

confidence: 91%

Doping dependence of d -wave bond-charge excitations in electron-doped cuprates

2019

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Motivated by the recent experiments reporting the doping dependence of the short-range charge order (CO) in electron-doped cuprates, we study the resonant x-ray scattering spectrum from dwave bond-charge fluctuations obtained in the two-dimensional t-J model. We find that (i) the CO is short-range, (ii) the CO peak is pronounced at low temperature, (iii) the peak intensity increases with decreasing carrier doping δ down to δ ≈ 0.10 and is substantially suppressed below δ ≈ 0.10 due to strong damping, and (iv) the momentum of the CO decreases monotonically down to δ ≈ 0.10 and goes up below δ ≈ 0.10. These results reasonably capture the major features of the experimental data, and the observed short-range CO can be consistently explained in terms of bond-charge fluctuations with an internal d-wave symmetry. PACS numbers:Recently resonant x-ray scattering (RXS), resonant inelastic x-ray scattering (RIXS), and high-energy x-ray scattering revealed the presence of short-range charge order (CO) with modulation vector along the axial direction (0, 0)-(π, 0) in various hole-doped cuprates (h-cuprates) such as Y-1-5 , Bi-6-9 , and Hg-based 10,11 compounds, implying that the CO can be a universal phenomenon in h-cuprates. The understanding of the origin of those charge correlations, therefore, will likely yield an important clue to the origin of the pseudogap as well as high-T c superconductivity 12 . In fact, a large number of theoretical studies were performed 13-22 , although a consensus has not been obtained.On the other hand, a short-range CO was also observed in electron-doped cuprates [23][24][25] (e-cuprates). Since the pseudogap features similar to those in h-cuprates are much weaker in e-cuprates, a theoretical study may be less complicated in e-cuprates. However, compared to theoretical studies of h-cuprates 13-22 , the CO in e-cuprates is much less studied [26][27][28][29] . Ref. 26 showed a comprehensive study of all possible COs in the two-dimensional (2D) t-J model and found a strong tendency to d-wave bond-charge order 30 . Ref. 27 then showed that d-wave bond-charge fluctuations can capture the charge excitation spectrum observed in experiments 23 . Although the theoretical framework is different from Refs. 26 and 27, similar d-wave bond-charge fluctuations were also proposed in Ref. 28 to explain the experimental data.The d-wave bond-charge order is different from a usual textbook-like charge-densitywave because the bond charge has an internal structure characterized by a d-wave symmetry.Therefore if the short-range CO observed in e-cuprates is indeed a d-wave bond-charge order, it can be interpreted as the first observation of unconventional CO in e-cuprates. Given that d-wave bond-charge order was discussed in h-cuprates 31 , it can be a universal phenomenon in the whole cuprate family. In addition, d-wave bond-charge order would be reduced to the electronic nematic order 32 , more precisely a d-wave Pomeranchuk instability 33-35 when the momentum transfer approaches zero. In this sense, the nematic ph...

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“…However, more work would be necessary before reaching such a conclusion. First, the CO was studied in the two-dimensional (2D) t-J model 27,31 , whereas the high-energy mode was analyzed in the layered t-J-V model 29 , with V being the long range Coulomb interaction. Thus, it is not clear whether the obtained insight about the CO in the 2D t-J model remains valid also in a more realistic model such as the layered t-J-V model.…”

Section: Introductionmentioning

confidence: 99%

Dual structure in the charge excitation spectrum of electron-doped cuprates

2017

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Motivated by the recent resonant x-ray scattering (RXS) and resonant inelastic x-ray scattering (RIXS) experiments for electron-doped cuprates, we study the charge excitation spectrum in a layered t-J model with the long-range Coulomb interaction. We show that the spectrum is not dominated by a specific type of charge excitations, but by different kinds of charge fluctuations, and is characterized by a dual structure in the energy space. Low-energy charge excitations correspond to various types of bond-charge fluctuations driven by the exchange term (J-term) whereas high-energy charge excitations are due to usual on-site charge fluctuations and correspond to plasmon excitations above the particle-hole continuum. The interlayer coupling, which is frequently neglected in many theoretical studies, is particularly important to the high-energy charge excitations.

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Strong particle-hole asymmetry of charge instabilities in doped Mott insulators

Cited by 16 publications

References 77 publications

d -wave bond-order charge excitations in electron-doped cuprates

d -wave bond-order charge excitations in electron-doped cuprates

Doping dependence of d -wave bond-charge excitations in electron-doped cuprates

Dual structure in the charge excitation spectrum of electron-doped cuprates

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