Research ArticleCONDENSED MATTER PHYSICS

Direct visualization of coexisting channels of interaction in CeSb

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Science Advances  01 Mar 2019:
Vol. 5, no. 3, eaat7158
DOI: 10.1126/sciadv.aat7158
  • Fig. 1 Magnetic and Kondo-like behavior in CeSb.

    (A) Temperature dependence of the electrical resistivity for semimetal CeSb and typical Kondo system CeCoIn5, coherence peak at T* ~ 35 and 45 K, respectively signaling the presence of the Kondo scattering at high temperature for both compounds. Although the absolute residual resistivity of CeSb is much greater than that of CeCoIn5 due to its semimetallic nature, the relative size of the resistivity upturn preceding T* is significantly smaller. (B) Electronic specific heat (Ce; black line with left axis) shows several magnetic transitions, from the AFM/PM transition at TN0 = 17 K to the AFM/FM-phase transitions at TNf = 8 K. Entropy (S; blue line with right axis) has been estimated by integrating the electronic specific heat, suggesting that spin degrees of freedom are restored at TK16K. (C) Schematic of the magnetic structure at each transition Ti across the so-called Devil’s staircase. Red arrows and gray circles present the direction of each FM and PM layers, respectively.

  • Fig. 2 CEF splitting.

    (A and B) The k-integrated f density of state (DOS) for on- and off-resonance ARPES data is displayed by red solid line and gray dashed line, respectively. Each f state is indicated by fΓ8 CEF, SO side-band peak and the f0 final-state peak in the range of binding energy (EB = EEF) between 0.1 and −4 eV. a.u., arbitrary units. (C) Crystal field scheme of cubic CeSb. SO separates J = 72 and 52 multiplets, and the latter is split by CEF into doublet fΓ7 and quartet fΓ8 manifolds, with fΓ7 forming the ground state. (D) Schematic of final-state shake-up transitions for Ce 4f1 including initial state hopping between the conduction electrons (c) and the f states. Excitation into fΓ8 CEF (or J = 7/2 SO split) f states results in lowered photoelectron kinetic energies at the detector and the appearance of these f states below EF.

  • Fig. 3 Observation of magnetic exchange splitting at X point.

    Schematic of CeSb’s band structure at X, (A) at T>TN0 (E) at T<TNf. (B to D) ARPES data taken at hv = 88 eV near the X point for the selected temperatures (indicated at the top left). A clear signature of band splitting has been detected at T = 6 K owing to Zeeman-like exchange splitting, which disappears above TN0.

  • Fig. 4 Observation of p-f hybridization at the Γ point.

    Schematic of CeSb’s band structure at Γ, (A) at T > T* and (C) at TT*. The schematic is a simplification and does not take into account orbital-dependent hybridization due to symmetry considerations nor the effect of final-state excitations. (B) Temperature dependence of the ARPES spectra showing strong evidence of p-f hybridization as the temperature is lowered. Note that a k-independent background has been subtracted from the spectral images (see section S5 and fig. S5). The on-resonance photon energy is 122 eV for kZ at the high-symmetry Γ point of the bulk BZ (see fig. S2A).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/3/eaat7158/DC1

    Section S1. Single impurity Ce 4f spectral weight

    Section S2. ARPES data on LaSb

    Section S3. Possible Weyl points within the fully ordered state

    Section S4. Comparison of Fermi surface for CeSb and LaSb

    Section S5. Background subtraction of the ARPES spectra at the Γ point

    Fig. S1. Single-impurity Ce 4f spectral weight.

    Fig. S2. Energy band dispersion at different photon energies and light polarizations.

    Fig. S3. ARPES data on LaSb.

    Fig. S4. Fermi surface map for CeSb and LaSb at hv = 122 and 88 eV, respectively.

    Fig. S5. Background subtraction of the ARPES spectra at the Γ point.

    References (32, 33)

  • Supplementary Materials

    This PDF file includes:

    • Section S1. Single impurity Ce 4f spectral weight
    • Section S2. ARPES data on LaSb
    • Section S3. Possible Weyl points within the fully ordered state
    • Section S4. Comparison of Fermi surface for CeSb and LaSb
    • Section S5. Background subtraction of the ARPES spectra at the Γ point
    • Fig. S1. Single-impurity Ce 4f spectral weight.
    • Fig. S2. Energy band dispersion at different photon energies and light polarizations.
    • Fig. S3. ARPES data on LaSb.
    • Fig. S4. Fermi surface map for CeSb and LaSb at hv = 122 and 88 eV, respectively.
    • Fig. S5. Background subtraction of the ARPES spectra at the Γ point.
    • References (32, 33)

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