Orbital-Ordering-Driven Multiferroicity and Magnetoelectric Coupling in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>GeV</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">S</mml:mi></mml:mrow><mml:mrow><mml:mn>8</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Singh, Kiran; Simon, Charles; Cannuccia, Elena; Lepetit, Marie-Bernadette; Corraze, B.; Janod, Étienne; Cario, Laurent

doi:10.1103/physrevlett.113.137602

Cited by 59 publications

(114 citation statements)

References 39 publications

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“…The 17 K AFM transition appears as a cusp in the susceptibility curve. The observed Néel temperature is consistent with previous reports that have ranged from 13 to 18 K. 7,15,16 The step-like transition observed at 31.5 K has been shown to be the consequence of a structural transition from cubic (possibly tetragonal, as noted above) to orthorhombic. 16 Above the structural transition at 31.5 K, the inverse susceptibilities are studied to discuss the Curie-Weiss behavior.…”

Section: Experimental Methodssupporting

confidence: 91%

Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8

et al. 2017

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We present an investigation of the multiferroic lacunar spinel compound GeV 4 S 8 using timedomain terahertz spectroscopy. We find three absorptions which either appear or shift at the antiferromagnetic transition temperature, TN = 17 K, as S=1 magnetic moments develop on vanadium tetrahedra. Two of these absorptions are coupled to the magnetic state and one only appears below the Néel temperature, and is interpreted as a magnon. We also observe isosbestic points in the dielectric constant in both the temperature and frequency domains. Further, we perform analysis on the isosbestic features to reveal an interesting collapse into a single curve as a function of both frequency and temperature, behavior which exists throughout the phase transitions. This analysis suggests the importance of spectral changes in the terahertz range which are linear in frequency and temperature.

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Section: Experimental Methodssupporting

confidence: 91%

Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8

et al. 2017

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“…Orbital excitations were found to be the key in understanding the temperature dependence of the resistivity and optical conductivity in the ferromagnetic phase of doped manganites [4]. The multiferroicity in GeV4S8 is thought to originate from an orbital ordering that reorganizes the charge within the transition metal clusters [5]. Furthermore, electron orbitals are considered to be the origin of the extremely anisotropic superconducting gap in the nematic phase of FeSe superconductors [6].…”

Section: Introductionmentioning

confidence: 99%

Orbital-flop Induced Magnetoresistance Anisotropy in Rare Earth Monopnictide CeSb

Bao

et al. 2019

Nat Commun

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The charge and spin of the electrons in solids have been extensively exploited in electronic devices and in the development of spintronics. Another attribute of electrons—their orbital nature—is attracting growing interest for understanding exotic phenomena and in creating the next-generation of quantum devices such as orbital qubits. Here, we report on orbital-flop induced magnetoresistance anisotropy in CeSb. In the low temperature high magnetic-field driven ferromagnetic state, a series of additional minima appear in the angle-dependent magnetoresistance. These minima arise from the anisotropic magnetization originating from orbital-flops and from the enhanced electron scattering from magnetic multidomains formed around the first-order orbital-flop transition. The measured magnetization anisotropy can be accounted for with a phenomenological model involving orbital-flops and a spin-valve-like structure is used to demonstrate the viable utilization of orbital-flop phenomenon. Our results showcase a contribution of orbital behavior in the emergence of intriguing phenomena.

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“…In most cases, the cubane-like metallic clusters are characterized by an only partly filled electronic shell and, hence, most of the lacunar spinels are Jahn-Teller active [8]. Recently, for GeV4S8 [9] and GaV4S8 [10] it has been shown that the onset of orbital order and the resulting Jahn-Teller distortion induces ferroelectricity, and, thus, these compounds are multiferroic. The polar dynamics in GaV4S8 at the phase transition has been probed by dielectric and THz spectroscopy [11].…”

Section: Introductionmentioning

confidence: 99%

Structural, magnetic, electric, dielectric, and thermodynamic properties of multiferroicGeV4S8

et al. 2016

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The lacunar spinel GeV4S8 undergoes orbital and ferroelectric ordering at the Jahn-Teller transition around 30 K and exhibits antiferromagnetic order below about 14 K. In addition to this orbitally driven ferroelectricity, lacunar spinels are an interesting material class, as the vanadium ions form V4 clusters representing stable molecular entities with a common electron distribution and a welldefined level scheme of molecular states resulting in a unique spin state per V4 molecule. Here we report detailed x-ray, magnetic susceptibility, electrical resistivity, heat capacity, thermal expansion, and dielectric results to characterize the structural, electric, dielectric, magnetic, and thermodynamic properties of this interesting material, which also exhibits strong electronic correlations. From the magnetic susceptibility, we determine a negative Curie-Weiss temperature, indicative for antiferromagnetic exchange and a paramagnetic moment close to a spin S = 1 of the V4 molecular clusters. The low-temperature heat capacity provides experimental evidence for gapped magnon excitations. From the entropy release, we conclude about strong correlations between magnetic order and lattice distortions. In addition, the observed anomalies at the phase transitions also indicate strong coupling between structural and electronic degrees of freedom. Utilizing dielectric spectroscopy, we find the onset of significant dispersion effects at the polar Jahn-Teller transition. The dispersion becomes fully suppressed again with the onset of spin order. In addition, the temperature dependencies of dielectric constant and specific heat possibly indicate a sequential appearance of orbital and polar order.

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Orbital-Ordering-Driven Multiferroicity and Magnetoelectric Coupling inGeV4S8

Cited by 59 publications

References 39 publications

Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8

Terahertz dielectric analysis and spin-phonon coupling in multiferroic GeV4S8

Orbital-flop Induced Magnetoresistance Anisotropy in Rare Earth Monopnictide CeSb

Structural, magnetic, electric, dielectric, and thermodynamic properties of multiferroicGeV4S8

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