Triplet excitations in low-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>spin-gap systems<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">KCuCl</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://ww

Cavadini, N.; Rüegg, Ch.; Furrer, A.; Güdel, Hans‐Ulrich; Krämer, Karl; Mutka, H.; Vorderwisch, P.

doi:10.1103/physrevb.65.132415

Cited by 45 publications

(33 citation statements)

References 24 publications

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“…The importance of INS results is reflected in the large number of groups that have devoted resources to studying powder and single-crystal samples of quantum magnets that are strong candidates for the observation of field-induced BEC QCPs including but not limited to Sasago et al (1997), Cavadini et al (2001Cavadini et al ( , 2002, Coldea et al (2002), Coldea, Tennant, and Tylczynski (2003), Rüegg et al (2003Rüegg et al ( , 2004Rüegg et al ( , 2007Rüegg et al ( , 2008, Masuda et al (2006), Stone et al (2006Stone et al ( , 2007Stone et al ( , 2008bStone et al ( , 2008c, Zapf et al (2006), , Zheludev et al (2007Zheludev et al ( , 2008, Hong et al (2008Hong et al ( , 2010, Kofu, Kim et al (2009), Thielemann, Rüegg, Rønnow et al (2009, Schmidiger et al (2011), andTsyrulin et al (2013).…”

Section: Inelastic Neutron Scatteringmentioning

confidence: 99%

Bose-Einstein condensation in quantum magnets

2014

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This article reviews experimental and theoretical work on Bose-Einstein condensation in quantum magnets. These magnets are natural realizations of gases of interacting bosons whose relevant parameters such as dimensionality, lattice geometry, amount of disorder, nature of the interactions, and particle concentration can vary widely between different compounds. The particle concentration can be easily tuned by applying an external magnetic field which plays the role of a chemical potential. This rich spectrum of realizations offers a unique possibility for studying the different physical behaviors that emerge in interacting Bose gases from the interplay between their relevant parameters. The plethora of other bosonic phases that can emerge in quantum magnets, of which the Bose-Einstein condensate is the most basic ground state, is reviewed. The compounds discussed in this review have been intensively studied in the last two decades and have led to important contributions in the area of quantum magnetism. In spite of their apparent simplicity, these systems often exhibit surprising behaviors. The possibility of using controlled theoretical approaches has triggered the discovery of unusual effects induced by frustration, dimensionality, or disorder.

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Section: Inelastic Neutron Scatteringmentioning

confidence: 99%

Bose-Einstein condensation in quantum magnets

2014

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“…2 In these case, antiferromagnetic order perpendicular to the field appears simultaneously with magnetization parallel to the field, creating field-induced magnetic order, 6 which can be interpreted as a condensation of the lowest lying magnon mode. 7,8,9,10,11,12,13,14,15 In contrast to these case, when the interaction energy dominates, magnetization plateaus can appear accompanied by a magnetic superlattice. 16 Such plateaus have been observed at a rational fraction of the saturation moment.…”

mentioning

confidence: 87%

Microscopic model for the magnetization plateaus inNH4CuCl3

Matsumoto

2003

Phys. Rev. B

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A simple model consisting of three distinct dimer sublattices is proposed to describe the magnetism of NH4CuCl3. It explains the occurrence of magnetization plateaus only at 1/4 and 3/4 of the saturation magnetization. The field dependence of the excitation modes observed by ESR measurements is also explained by the model. The model predicts that the magnetization plateaus should disappear under high pressure.PACS numbers: 75.30. Cr, NH 4 CuCl 3 , TlCuCl 3 , and KCuCl 3 are isostructual quantum spin systems consisting of two-leg ladders separated by NH + 4 , Tl + , and K + ions. The two-leg ladders are composed of Cu 2+ ions with spin S = 1/2 which interact antiferromagnetically (AF) through the Cl − ions. These compounds can be considered as coupled two-leg S = 1/2 Heisenberg AF spin ladders, and show various types of magnetization curves. Shiramura et al. found that NH 4 CuCl 3 has magnetization plateaus at 1/4 and 3/4 of the saturation moment, 1 while TlCuCl 3 and KCuCl 3 have no plateaus in their magnetization curves. 2 For NH 4 CuCl 3 , Kurniawan et al. performed ESR experiments which revealed that NH 4 CuCl 3 has a finite excitation gap in the plateau regions. 3 By studying specific heat, they found AF order already at zero field and suggested a phase diagram in finite fields containing three magnetically ordered phases. 4 The origin of magnetization plateaus has attracted much interest recently. For weakly interacting dimer systems, the ground state is a spin singlet liquid with only short-range correlations between spins, and the triplet excitations require a finite excitation energy. An excited gas of triplet magnons has two characteristic energies. 5 Exchange interactions cause the transfer of excited triplets between neighboring dimers leading to a form of kinetic energy. They also lead to a short range repulsion between triplets in addition to the hard core repulsion forbidding double occupancy of a dimer. The triplet excitations are split in an external magnetic field, and the energy of the lowest component can be driven through zero. When the kinetic energy is dominant, which is realized in TlCuCl 3 and KCuCl 3 , we have no plateaus in the magnetization curve. 2 In these case, antiferromagnetic order perpendicular to the field appears simultaneously with magnetization parallel to the field, creating field-induced magnetic order, 6 which can be interpreted as a condensation of the lowest lying magnon mode. 7,8,9,10,11,12,13,14,15 In contrast to these case, when the interaction energy dominates, magnetization plateaus can appear accompanied by a magnetic superlattice. 16 Such plateaus have been observed at a rational fraction of the saturation moment. 1,17 In SrCu 2 (BO 3 ) 2 , the frustrated form of the dimer lattice leads to a narrow bandwidth for triplet excitations and magnetization plateaus associated with a magnetic superlattice of localized triplets. 18,19 An unexpected feature of NH 4 CuCl 3 is the absence of a magnetization plateau at a value 1/2 of the saturation magnetization although this...

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“…The ground state of isolated antiferromagnetic spin clusters is given by either a spin singlet or a spin triplet state 1,2 . Applying an external field or pressure, on the one hand, can induce long-range magnetic order [3][4][5][6][7][8][9][10][11][12][13] . On the other hand, intercluster interactions can render the discrete energy level of an isolated cluster to form an energy band.…”

Section: Introductionmentioning

confidence: 99%

Anomalous spin dynamics in the coupled spin tetramer systemCuSeO3

Lee

Tol

et al. 2017

Phys. Rev. B

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We report high-field magnetization, high-frequency electron spin resonance (ESR), and 77 Se nuclear magnetic resonance (NMR) measurements on the linear spin tetramer system CuSeO 3 , consisting of strongly interacting Cu(1) dimers and weakly coupled Cu(2) spins. The magnetization exhibits anisotropic half-step magnetization plateaux at µ 0 H = 45 T, depending on a crystallographic orientation. A temperature dependence of the ESR linewidth ∆H pp in a paramagnetic phase points towards the significance of anisotropic exchange interactions. Below T N = 9 − 10 K long-range magnetic order is evidenced by the observation of a critical divergence of both ∆H pp (T ) and the nuclear spin-lattice relaxation rate 1/T 1 . In addition, we identify a magnetic anomaly at T * = 6.0(5) K below T N , which is caused by a spin reorientation. The nuclear spin-spin relaxation rate 1/T 2 unveils the development of site-specific spin correlations. The intriguing magnetism of CuSeO 3 is discussed in terms of the energy hierarchy of Cu(1) and Cu(2) spins in concert with additional intertetramer interactions.

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Triplet excitations in low-Hcspin-gap systemsKCuCl3and
N. Cavadini
¹
,
Ch. Rüegg
²
,
A. Furrer
³

et al.

Cited by 45 publications

References 24 publications

Bose-Einstein condensation in quantum magnets

Bose-Einstein condensation in quantum magnets

Microscopic model for the magnetization plateaus inNH4CuCl3

Anomalous spin dynamics in the coupled spin tetramer systemCuSeO3

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Triplet excitations in low-Hcspin-gap systemsKCuCl3andN. Cavadini1, Ch. Rüegg2, A. Furrer3 et al.

Cited by 45 publications

References 24 publications

Bose-Einstein condensation in quantum magnets

Bose-Einstein condensation in quantum magnets

Microscopic model for the magnetization plateaus inNH4CuCl3

Anomalous spin dynamics in the coupled spin tetramer systemCuSeO3

Contact Info

Product

Resources

About

Triplet excitations in low-Hcspin-gap systemsKCuCl3and
N. Cavadini
¹
,
Ch. Rüegg
²
,
A. Furrer
³

et al.