Kondo hybridization and quantum criticality in $\ensuremath{\beta}\ensuremath{-}{\mathrm{YbAlB}}_{4}$ by laser ARPES

Kondo hybridization and quantum criticality in $β - {YbAlB}_{4}$ by laser ARPES

Cédric Bareille, Shintaro Suzuki, Mitsuhiro Nakayama, Kenta Kuroda, Andriy H. Nevidomskyy, Yosuke Matsumoto, Satoru Nakatsuji, Takeshi Kondo, and Shik Shin

Phys. Rev. B 97, 045112 – Published 10 January 2018

Abstract

We report an angle-resolved photoemission (ARPES) study of $β - {YbAlB}_{4}$ , which is known to harbor unconventional quantum criticality (QC) without any tuning. We directly observe a quasiparticle peak (QP) emerging from hybridization, characterized by a binding energy and an onset of coherence both at about 4 meV. This value conforms with a previously observed reduced Kondo scale at about 40 K. Consistency with an earlier study of carriers in $β - {YbAlB}_{4}$ via the Hall effect strongly suggests that this QP is responsible for the QC in $β - {YbAlB}_{4}$ . A comparison with the sister polymorph $α - {YbAlB}_{4}$ , which is not quantum critical at ambient pressure, further supports this result. Indeed, within the limitation of our instrumental resolution, our ARPES measurements do not show tangible sign of hybridization in this locally isomorphic system, while the conduction band we observe is essentially the same as in $β - {YbAlB}_{4}$ . We therefore claim that we identified by ARPES the carriers responsible for the QC in $β - {YbAlB}_{4}$ . The observed dispersion and the underlying hybridization of this QP are discussed in the context of existing theoretical models.

Received 16 June 2017
Revised 29 October 2017

DOI:https://doi.org/10.1103/PhysRevB.97.045112

Physics Subject Headings (PhySH)

Electronic structure Quantum criticality Quasiparticles & collective excitations

Heavy-fermion systems Strongly correlated systems

Angle-resolved photoemission spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Cédric Bareille^1,*, Shintaro Suzuki¹, Mitsuhiro Nakayama¹, Kenta Kuroda¹, Andriy H. Nevidomskyy², Yosuke Matsumoto³, Satoru Nakatsuji^1,4, Takeshi Kondo¹, and Shik Shin¹

¹ISSP, University of Tokyo, Kashiwa 277-8581, Japan
²Department of Physics and Astronomy & Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
³Max Planck Institute for Solid State Research, Heisenbergstrasse 1, Stuttgart 70569, Germany
⁴CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan

^*bareille@issp.u-tokyo.ac.jp

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 97, Iss. 4 — 15 January 2018

Reuse & Permissions

Access Options

Article Available via CHORUS

Download Accepted Manuscript

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
(a) Representation from the $c$ axis of the crystal structure of $β - {YbAlB}_{4}$ (left) and $α - {YbAlB}_{4}$ (right). (b) Brillouin zone of $β - {YbAlB}_{4}$ . (c) Mapping in the (100) plane, 50 meV below $E_{F}$ . Full black lines are the edges of the BZ. Purple circles show the position reached with a light of $h ν = 6.994$ and 54 eV. (d) Dispersion at normal emission, i.e., along the $〈001〉$ direction. (e) Laser-ARPES spectra on $β - {YbAlB}_{4}$ ; $h ν = 6.994$ eV.
Reuse & Permissions
Figure 2
Laser-ARPES on $β - {YbAlB}_{4}$ . (a) Stack of EDCs next to $\tilde{Z}$ , along the full gray line $A$ in panel (b). Green markers are peak position from EDCs, fitted by Voigt with a quadratic background and cut by a Fermi-Dirac step. Detailed fitting for $k_{y} = - 0.15$ , 0, and 0.15 $Å^{- 1}$ are illustrated with Fig. S2 of the Supplemental Material [16]. (b) Fermi-surface mapping performed by tuning the polar angle. Sketch on the right illustrates the geometry of the measurements; the analyzer slit was oriented along the line $A$ . The blue circle shows the little electronlike Fermi sheet, while the two red arrows show an outer Fermi sheet. Black lines are edges of the BZ. (c) Curvature of the ARPES spectra measured along the slit of the analyzer [full gray line in panel (b)]. Green markers are peak position as of panel (a). The blue, red, and pink lines are the results of the modeling based on the constant hybridization of the original bands (represented by dashed black lines). (d) Same as (c) with a $k$ -dependent nodal potential. See the Supplemental Material for the raw data (Fig. S3) and details of the hybridization models [16]. (e) Curvature of the cut along the $〈010〉$ direction [dashed gray line $B$ in panel (b)]. Green markers are peak position from EDC fit. Full blue, red, and pink lines are guides to the eye. See Fig. S3 of the Supplemental Material for the raw data [16].
Reuse & Permissions
Figure 3
Temperature dependence on $β - {YbAlB}_{4}$ . (a) EDCs at $k_{y} = 0 Å^{- 1}$ from $T = 5$ to 60 K. (b) EDCs at $k_{y} = 0.17 Å^{- 1}$ from $T = 5$ to 60 K. [The peak's intensity difference with EDC in Fig. 2 is due to a slightly different orientation along the slit, as temperature dependence was performed on a different sample—see Fig. S1 of the Supplemental Material for the corresponding color scale 16]. (c) Intensity, relative to the value at 60 K, of the inner (outer) peak from EDCs divided by the Fermi-Dirac step and integrated along the shade area of panel (a) [(b)].
Reuse & Permissions
Figure 4
Laser-ARPES on $α - {YbAlB}_{4}$ . (a) Curvature of the spectra along the $〈100〉$ direction. Open and full circles are peak positions, extracted, respectively, from EDCs and MDCs. See Fig. S3 of the Supplemental Material for the raw data [16]. (b) MDC stack of previous panel. Black markers are peak positions for the electronlike band. They were obtained by fitting MDCs by Voigts with a constant background.
Reuse & Permissions
Figure 5
(a) MDC and EDC fits (open and full markers) from $α - {YbAlB}_{4}$ compared to EDC fit on $β - {YbAlB}_{4}$ (blue, red, and pink lines). The broken black lines denote the unhybridized electronlike conduction band and Yb $4 f$ flat bands from the same model as in Fig. 2. (b) EDCs at $k = 0$ ; $\pm 0.15 Å^{- 1}$ from $β - {YbAlB}_{4}$ (red) and $α - {YbAlB}_{4}$ (green). In the left panel is the raw, while the right panel shows the EDCs divided by the effective Fermi-Dirac step. Open arrows indicate the $|\pm 5 / 2〉$ level, while full arrows indicate the $|\pm 3 / 2〉$ level.
Reuse & Permissions

Physical Review B

covering condensed matter and materials physics

Kondo hybridization and quantum criticality in $β - {YbAlB}_{4}$ by laser ARPES

Cédric Bareille, Shintaro Suzuki, Mitsuhiro Nakayama, Kenta Kuroda, Andriy H. Nevidomskyy, Yosuke Matsumoto, Satoru Nakatsuji, Takeshi Kondo, and Shik Shin

Phys. Rev. B 97, 045112 – Published 10 January 2018

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

Article Text (Subscription Required)

Supplemental Material (Subscription Required)

References (Subscription Required)

Issue

Access Options

Physical Review B

covering condensed matter and materials physics

Kondo hybridization and quantum criticality in β−YbAlB4 by laser ARPES

Cédric Bareille, Shintaro Suzuki, Mitsuhiro Nakayama, Kenta Kuroda, Andriy H. Nevidomskyy, Yosuke Matsumoto, Satoru Nakatsuji, Takeshi Kondo, and Shik Shin

Phys. Rev. B 97, 045112 – Published 10 January 2018

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

Article Text (Subscription Required)

Supplemental Material (Subscription Required)

References (Subscription Required)

Issue

Access Options

Authorization Required

Other Options

Download & Share

Images

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Log In

Search

Article Lookup

Paste a citation or DOI

Enter a citation

Kondo hybridization and quantum criticality in $β - {YbAlB}_{4}$ by laser ARPES