Decay and renormalization of a longitudinal mode in a quasi-two-dimensional antiferromagnet

AbstractAn ongoing challenge in the study of quantum materials, is to reveal and explain collective quantum effects in spin systems where interactions between different modes types are important. Here we approach this problem through a combined experimental and theoretical study of interacting transverse and longitudinal modes in an easy-plane quantum magnet near a continuous quantum phase transition. Our inelastic neutron scattering measurements of Ba2FeSi2O7 reveal the emergence, decay, and renormalization of a longitudinal mode throughout the Brillouin zone. The decay of the longitudinal mode is particularly pronounced at the zone center. To account for the many-body effects of the interacting low-energy modes in anisotropic magnets, we generalize the standard spin-wave theory. The measured mode decay and renormalization is reproduced by including all one-loop corrections. The theoretical framework developed here is broadly applicable to quantum magnets with more than one type of low energy mode.

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Decay and renormalization of a longitudinal mode in a quasi-two-dimensional antiferromagnet

10.21203/rs.3.rs-272733/v1 ◽

2021 ◽

Author(s):

Seung-Hwan Do ◽

Hao Zhang ◽

Travis Williams ◽

Tao Hong ◽

Vasile Garlea ◽

...

Keyword(s):

Theoretical Study ◽

Inelastic Neutron Scattering ◽

Longitudinal Mode ◽

Wave Theory ◽

Inelastic Neutron ◽

Spin Systems ◽

Longitudinal Modes ◽

Quantum Magnet ◽

Energy Mode ◽

The One

Abstract An ongoing challenge in the study of quantum materials, is to reveal and explain collective quantum effects in spin systems where interactions between different modes types are important. Here we approach this problem through a combined experimental and theoretical study of interacting transverse and longitudinal modes in an easy-plane quantum magnet near a continuous quantum phase transition. Our inelastic neutron scattering measurements of Ba2FeSi2O7 reveal the emergence, decay, and renormalization of a longitudinal mode throughout the Brillouin zone. The decay of the longitudinal mode is particularly pronounced at the zone center. To explain these observations, we develop a generalized linear spin-wave theory, including all of the one-loop corrections, which reproduces the measured mode decay and renormalization. The theoretical approach developed here is broadly applicable to quantum magnets with more than one type of low energy mode.

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Weyl-triplons in SrCu2(BO3)2

10.21203/rs.3.rs-52442/v1 ◽

2020 ◽

Author(s):

Pinaki Sengupta ◽

DHIMAN BHOWMICK

Keyword(s):

Magnetic Field ◽

Longitudinal Magnetic Field ◽

Inelastic Neutron Scattering ◽

Three Dimensional ◽

Inelastic Neutron ◽

Nodal Line ◽

Low Energy ◽

Zero Field ◽

Quantum Magnet ◽

The Individual

Abstract Presence of Weyl node, nodal line or nodal surface in the band structure is a signature of topological gapless phase in a three-dimensional(3D) material. Here, we propose that Weyl triplons are expected to appear in the low energy magnetic excitations in the canonical Shastry-Sutherland compound, \ce{SrCu2(BO3)2}, a quasi-2D quantum magnet. Our results show that whena minimal, realistic inter-layer coupling is added to the well-established microscopicmodel describing the excitation spectrum of the individual layers,the Dirac points that appears in the zero-field triplon spectrum of the 2D modelsplits into two pairs of Weyl points along the Kz direction. Varying the strength of the inter-layer Dzyaloshinskii–Moriya(DM) interaction and applying asmall longitudinal magnetic field results in a range of band topologytransitions accompanied by changing numbers of Weyl points. We propose inelastic neutron scattering along with thermal Hall effect as the experimental techniques to detect the presence of Weyl-node in the triplon spectrum of this material.

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Van Hove singularity in the magnon spectrum of the antiferromagnetic quantum honeycomb lattice

Nature Communications ◽

10.1038/s41467-020-20335-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

G. Sala ◽

M. B. Stone ◽

Binod K. Rai ◽

A. F. May ◽

Pontus Laurell ◽

...

Keyword(s):

Disordered Systems ◽

Inelastic Neutron Scattering ◽

Magnetic Moments ◽

Wave Theory ◽

Inelastic Neutron ◽

Quantum Spin ◽

Honeycomb Lattice ◽

Quantum Magnetism ◽

Van Hove Singularity ◽

Sharp Feature

AbstractIn quantum magnets, magnetic moments fluctuate heavily and are strongly entangled with each other, a fundamental distinction from classical magnetism. Here, with inelastic neutron scattering measurements, we probe the spin correlations of the honeycomb lattice quantum magnet YbCl3. A linear spin wave theory with a single Heisenberg interaction on the honeycomb lattice, including both transverse and longitudinal channels of the neutron response, reproduces all of the key features in the spectrum. In particular, we identify a Van Hove singularity, a clearly observable sharp feature within a continuum response. The demonstration of such a Van Hove singularity in a two-magnon continuum is important as a confirmation of broadly held notions of continua in quantum magnetism and additionally because analogous features in two-spinon continua could be used to distinguish quantum spin liquids from merely disordered systems. These results establish YbCl3 as a benchmark material for quantum magnetism on the honeycomb lattice.

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Low-energy magnetic response of the noncentrosymmetric heavy-fermion superconductorCePt3Sistudied via inelastic neutron scattering

Physical Review B ◽

10.1103/physrevb.78.184518 ◽

2008 ◽

Vol 78 (18) ◽

Cited By ~ 15

Author(s):

B. Fåk ◽

S. Raymond ◽

D. Braithwaite ◽

G. Lapertot ◽

J.-M. Mignot

Keyword(s):

Neutron Scattering ◽

Heavy Fermion ◽

Inelastic Neutron Scattering ◽

Inelastic Neutron ◽

Low Energy ◽

Magnetic Response

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Inelastic neutron scattering and low-energy excitation of amorphous SF6 hydrate prepared by vapor-deposition technique

Canadian Journal of Physics ◽

10.1139/p02-140 ◽

2003 ◽

Vol 81 (1-2) ◽

pp. 107-114 ◽

Cited By ~ 4

Author(s):

O Yamamuro ◽

T Matsuo ◽

I Tsukushi ◽

N Onoda-Yamamuro

Keyword(s):

Neutron Scattering ◽

Inelastic Neutron Scattering ◽

Inelastic Neutron ◽

Annealed Sample ◽

Low Energy ◽

Energy Excitation ◽

Hydrogen Bond Formation ◽

Crystalline Sample ◽

Two Samples ◽

Vapor Deposition Technique

Amorphous SF6 hydrate (SF6·17H2O) was prepared by depositing the mixed vapor onto a substrate kept at about 8 K. The inelastic neutron-scattering spectra of the as-deposited sample and those annealed at about 120 and 150 K were measured at 50 K in the energy range below 100 meV. The first two samples were considered to be in amorphous states while the third one was in a crystalline state. The librational frequency of the water molecule (at around 60 meV) is smaller in the order of (as-deposited sample) < (annealed sample) < (crystalline sample). This indicates that the strength of the intermolecular hydrogen bonds is (crystalline sample) > (annealed sample) > (as-deposited sample). The spectra below 10 meV were compared with our previous data of pure vapor-deposited amorphous ices and those doped with methanol (CD3OH). The low-energy excitation (E < 6 meV) differed drastically depending on the dopants, i.e., the scattering intensity was enhanced by methanol doping but reduced by SF6 doping. This may be because the hydrogen-bond formation was hindered by methanol doping but promoted rather more by SF6 doping because of the hydrophobic interaction as in clathrate hydrates. PACS Nos.: 61.12Ex, 63.50tx

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The investigation of Neutron Scattering In Spin Waves Theory of Ferromagnetic Crystals

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v8n4.151 ◽

2014 ◽

Vol 8 (4) ◽

Author(s):

Azadeh Farzaneh ◽

Mohammad Reza Abdi ◽

Khadije Rezaee Ebrahim Saraee

Keyword(s):

Neutron Scattering ◽

Spin Wave ◽

Cross Section ◽

Inelastic Neutron Scattering ◽

Spin Waves ◽

Wave Theory ◽

Spin Correlation ◽

Inelastic Neutron ◽

Magnetic Behaviour ◽

Spin Interaction

Inelastic neutron scattering, probing the temporal spin-spin correlation at the different microscopic scale, is a powerful technique to study the magnetic behaviour of ferromagnetic crystals. In addition, high penetration power of neutron in samples has made it as a useful way for spin-spin interaction in neutron scattering. Changes in the magnetic cross section in term of different energy transfer and temperatures are calculated for nickel and iron as transition metals in Heisenberg model versus spin wave theory by considering atomic form factor. Finally, the effect of magnetic structure and behaviour of crystal in measuring cross-section shows that increasing temperature results in the Cross-section increase Also, the existence of propagating spin waves below Tc is compared in Ni and Fe in different momentum transfers. The relation of spin wave energy with temperature dependence of nickel has created different behaviour in the changes of cross section rather than iron.

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Spin Dynamics in the Metallic State of YBa2(Cu0.98 Zn0.02) 3O6+x

International Journal of Modern Physics B ◽

10.1142/s021797929800257x ◽

1998 ◽

Vol 12 (29n31) ◽

pp. 3330-3334 ◽

Cited By ~ 2

Author(s):

Y. Sidis ◽

P. Bourges ◽

B. Hennion ◽

R. Villeneuve ◽

G. Collin ◽

...

Keyword(s):

Inelastic Neutron Scattering ◽

Spin Dynamics ◽

Inelastic Neutron ◽

Resonance Peak ◽

Low Energy ◽

Metallic State ◽

Magnetic Fluctuations ◽

Local Enhancement ◽

Compound I ◽

Nonmagnetic Impurities

Inelastic neutron scattering measurements have been carried out on a YBa2(Cu0.98-Zn0.02)3O 6+x single crystal in both underdoped (x = 0.7) and overdoped (x = 0.97) regimes. In the zinc substituted system, spin dynamics is drastically changed in respect to the pure compound: (i) the "resonance peak" almost vanishes, (ii) the spin gap is filled, (iii) new antiferromagnetic excitations are found at low energy. These new magnetic fluctuations, which persist in the normal state, account for a local enhancement of AF correlations around nonmagnetic impurities. Besides, it is worth emphasizing that features, not directly related to superconductivity, i.e., the contribution to the spin dynamics apart from the resonance peak and the "spin pseudo-gap" observed in the underdoped regime above T c , coexist with the new low energy magnetic fluctuations.

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