Direct Observation of Localized Spin Antiferromagnetic Transition in PdCrO2 by Angle-Resolved Photoemission Spectroscopy

Noh, Han-Jin; Jeong, Jaehoon; Chang, Bin; Jeong, Dahee; Moon, Hyun Sook; Cho, En-Jin; Ok, Jong Mok; Kim, Jun Sung; Kim, Kyoo; Min, B. I.; Lee, Han-Koo; Kim, Jae‐Young; Park, Byeong‐Gyu; Kim, Hyeong–Do; Lee, Seongsu

doi:10.1038/srep03680

Cited by 50 publications

(52 citation statements)

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“…Intriguingly though, the k-space map obtained by integrating spectra over a narrow window around E − E F = 50 meV does not show a marked redistribution of spectral weight as it is a characteristic for nesting driven itinerant spin-density wave phases. 46,47 While these findings do not exclude AF ordering in LNO as it was invoked in Ref. 28 to explain the exchange bias observed in superlattices with 7 MLs LNO, 24,28 they suggest that the insulating behavior of thin LNO layers in LNO/LMO superlattices is triggered by a gradual loss of quasiparticle coherence, rather than a well-defined phase transition to a magnetically ordered state.…”

confidence: 78%

Electronic structure of buried LaNiO3 layers in (111)-oriented LaNiO3/LaMnO3 superlattices probed by soft x-ray ARPES

et al. 2017

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Taking advantage of the large electron escape depth of soft x-ray angle resolved photoemission spectroscopy we report electronic structure measurements of (111)oriented [LaNiO3/LaMnO3] superlattices and LaNiO3 epitaxial films. For thin films we observe a 3D Fermi surface with an electron pocket at the Brillouin zone center and hole pockets at the zone vertices. Superlattices with thick nickelate layers present a similar electronic structure. However, as the thickness of the LaNiO3 is reduced the superlattices become insulating. These heterostructures do not show a marked redistribution of spectral weight in momentum space but exhibit a pseudogap of ≈ 50 meV. Main TextWith the advancement of synthesis techniques it is possible nowadays to control the growth of transition metal oxide (TMO) epitaxial heterostructures at the unit cell level. The realization of such heterostructures have resulted in the discovery of fascinating phenomena as a consequence of the confinement of strongly correlated electrons in ultrathin high quality layers. [1-3] Since these thin layers are embedded in heterostructures, interfacial phenomena such as charge transfer and magnetic coupling play an important role together with dimensionality in determining the ground state of the system. [4-8] The recent development of combined angle-resolved photoemission spectroscopy (ARPES) and oxide heterostructures growth setups has allowed the electronic structure of TMO heterostructures to be probed directly.

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confidence: 78%

Electronic structure of buried LaNiO3 layers in (111)-oriented LaNiO3/LaMnO3 superlattices probed by soft x-ray ARPES

et al. 2017

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“…The nonmagnetic unit cell contains three layers: the offset of the Cr layers with respect to each other introduces an ABCABC stacking. The √ 3 × √ 3 reconstruction associated with 120 • magnetic order is observed in quantum oscillation [5,13], angle-resolved photoemission [12,14], and neutron data [4,11]; early signs of it appear at ∼60 K [15]. The neutron data also suggest a doublek magnetic structure (where k is a propagation vector of the magnetic structure), with simultaneous ferroic and antiferroic interplane correlations.The study of Takatsu et al (Ref.…”

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confidence: 93%

“…Therefore, if resistivity is measured while ramping the applied stress across zero, it is reasonable to hypothesize that a step-like feature should appear when the domains re-orient, corresponding to the resistive anisotropy within a domain. Detectable resistivity anisotropy is more likely to appear in the inelastic than the elastic component, because ARPES data indicate that the Fermi surface remains highly symmetric below T N [14,19]. (Although the samples will not have been detwinned in the ARPES studies, the observed Fermi surfaces remain sharp and highly isotropic modulo six-fold rotation symmetry.)…”

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confidence: 99%

Magnetic frustration and spontaneous rotational symmetry breaking in PdCrO2

et al. 2019

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In the triangular layered magnet PdCrO2 the intralayer magnetic interactions are strong, however the lattice structure frustrates interlayer interactions. In spite of this, long-range, 120 • antiferromagnetic order condenses at TN = 38 K. We show here through neutron scattering measurements under in-plane uniaxial stress and in-plane magnetic field that this occurs through a spontaneous lifting of the three-fold rotational symmetry of the nonmagnetic lattice, which relieves the interlayer frustration. We also show through resistivity measurements that uniaxial stress can suppress thermal magnetic disorder within the antiferromagnetic phase.At 24 K, solid oxygen undergoes a simultaneous Néel transition and rhombohedral to monoclinic structural transition [1,2]. The structural transition is driven by magnetic frustration: the monoclinic distortion introduces a preferred direction that relieves interlayer frustration [3]. The delafossite compound PdCrO 2 is also a rhombohedral system with interlayer magnetic frustration. The Cr sites in each layer are triangularly coordinated, and host S = 3 2 spins that start to arrange themselves into short-range, 120 • antiferromagnetic order at 200-300 K [4-7]. However Cr sites in each layer are centered between the Cr sites in adjacent layers, which frustrates the interlayer coupling. As the temperature is reduced to just above T N = 38 K, the in-plane correlation length grows to ∼20 lattice spacings without appearance of interplane coherence [8,9]. Then at T N the layers lock together to form long-range order at a transition that appears to be weakly first-order [5,24]. By analogy with solid oxygen and a related compound, CuCrO 2 [10], this could through a spontaneous rotational symmetry breaking and associated structural distortion that relieves interlayer frustration. However so far no structural distortion has been detected in PdCrO 2 [6,11].It is an important point to resolve, to understand the mechanisms by which magnetic order condenses on frustrated lattices, and here we take a different approach: using symmetry-breaking fields to polarize domains, if they are present. We employ neutron scattering measurements under in-plane uniaxial stress and magnetic field, and resistivity measurements under uniaxial stress. In PdCrO 2 the CrO 2 layers are Mott insulating, but are interleaved with highly conducting Pd sheets [12]. Com-parison with PdCoO 2 , which is nonmagnetic but otherwise has a nearly identifal Fermi surface (including the Fermi velocity) to PdCrO 2 , shows that magnetic scattering is the largest component of the inelastic resistivity of PdCrO 2 [5].In Fig. 1(a) we illustrate the nonmagnetic lattice. The nonmagnetic unit cell contains three layers: the offset of the Cr layers with respect to each other introduces an ABCABC stacking. The √ 3 × √ 3 reconstruction associated with 120 • magnetic order is observed in quantum oscillation [5,13], angle-resolved photoemission [12,14], and neutron data [4,11]; early signs of it appear at ∼60 K [15]. The neutron data also s...

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“…This reconstruction is observed via photoemission above and below T N [14,15], and the reconstructed bands are seen at low temperature by quantum oscillation measurements [16,17]. The resistivity shows a small sharp drop at T N , while the Hall effect becomes non-linear with magnetic field below T N [16,18], a sign of multi-band conduction in a clean metal.…”

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confidence: 98%

“…Spectroscopic probes of the bandstructure [14][15][16][17] suggest that the bandstructure of PdCrO 2 at T > T N is very similar to that of the non-magnetic analogue PdCoO 2 , scaled slightly to account for the difference in lattice parameter. The application of a finite U = 5 eV on the Co site was found to produce a Fermi surface in better agreement with dHvA measurements [29] and so we present results for both U = 0 and U = 5 eV.…”

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confidence: 99%

Impact of short-range order on transport properties of the two-dimensional metalPdCrO2

et al. 2015

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We study the Hall and Nernst effects across the antiferromagnetic transition that reconstructs the quasi-2D Fermi surface of the metallic local moment antiferromagnet PdCrO2. We show that nonmonotonic temperature dependence in the Hall effect and a sign change in the Nernst effect above the ordering temperature cannot be understood within a simple single-band transport model. The inclusion of coherent scattering by critical antiferromagnetic fluctuations can qualitatively account for these features in the transport coefficients. We discuss the implications of this for the pseudogap phase of the cuprate superconductors, which have a similar Fermi surface and where the same transport signatures are observed.PACS numbers: 72.15. Eb,72.15.Jf,72.15.Gd,72.10.Di The precursor phase to a continuous phase transition generically consists of a regime of critical fluctuations of the order parameter, the spectrum of which is controlled only by the broken symmetry associated with the ordered phase [1]. Superconductivity, for example, is preceded by paraconductivity, where superconducting fluctuations contribute to the conductivity even above the transition temperature. Characteristics of the superconducting state such as the correlation length can be extracted from the paraconducting regime [2,3]. In general, however, the impact of symmetry breaking on transport properties depends on the details of the electronic structure.One view of the pseudogap phase of the cuprate superconductors is that it is the precursor to some asyet unidentified order. This view is supported by the quantum oscillation [4], Hall [5] and Nernst [6,7] effect measurements which indicate that the Fermi surface is reconstructed, at least when superconductivity is suppressed by strong magnetic fields. The fact that the transport properties change without apparent discontinuities makes the identification of the ordered state difficult. Short-range charge order has, however, been detected in the pseudogap phase [8][9][10], and this should have an impact on transport properties [11].Here we study the model metallic single-band local moment antiferromagnet PdCrO 2 , and show that the critical fluctuations of the antiferromagnetic precursor phase modify the transport properties in a way that foreshadows the broken symmetry phase. The Hall and Nernst effect prove particularly sensitive to the precursor phase, with non-monotonic temperature dependence and unexpected sign changes. Including coherent magnetic scattering in a semi-classical transport calculation allows us to model these essential features. The simple quasi-2D Fermi surface makes this system a useful nonsuperconducting analogue to the cuprates. Comparison with the isostructrual non-magnetic material PdCoO 2 is also instructive.The delafossite oxide PdCrO 2 is a frustrated triangular-lattice antiferromagnet. It is unusual in that it combines highly anisotropic, very metallic conduction with local moment magnetism [12]. Triangular Pd layers giving rise to a simple single quasi-2D Fermi surface sheet...

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Direct Observation of Localized Spin Antiferromagnetic Transition in PdCrO2 by Angle-Resolved Photoemission Spectroscopy

Cited by 50 publications

References 25 publications

Electronic structure of buried LaNiO3 layers in (111)-oriented LaNiO3/LaMnO3 superlattices probed by soft x-ray ARPES

Electronic structure of buried LaNiO3 layers in (111)-oriented LaNiO3/LaMnO3 superlattices probed by soft x-ray ARPES

Magnetic frustration and spontaneous rotational symmetry breaking in PdCrO2

Impact of short-range order on transport properties of the two-dimensional metalPdCrO2

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