NMR investigation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>BaCu</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">V</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:mrow></mml:math>in alternating-chain and dimer-chain models

Lue, Chin‐Shan; Xie, Bingxing

doi:10.1103/physrevb.72.052409

Cited by 28 publications

(25 citation statements)

References 23 publications

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“…In this way, one can identify strongly correlated systems which retain their coherence at elevated temperatures. Our second key result is that we unambiguously established the relevant Hamiltonian of BaCu 2 V 2 O 9 revealing that it is a rare example of an alternating AFM-FM chain and correcting all previous results which assumed it to be an alternating AFM-AFM chain or an isolated dimer system [25,26,[35][36][37]. This finding implies our third key result that strong correlations in dimerized quantum magnets at elevated temperatures are independent of the sign of the interdimer exchange coupling.…”

supporting

confidence: 68%

“…However, in contrast to these predictions and to all previous experimental work [25,34,36,37] which assumed both interactions to be AFM, we demonstrate that the weaker interdimer coupling is FM. While we cannot determine which of the two exchange paths is FM, it is most likely that J 1 = J intra is AFM, while J 2 = J inter is FM.…”

contrasting

confidence: 56%

“…1(a)). Previous χ DC [25,[34][35][36], specific heat [25] and 51 V nuclear magnetic resonance [36,37] measurements revealed a non-magnetic ground state with excitations above a gap of size ∆ ≈ 31.0 − 40.5 meV. This implies that the Cu 2+ ions are coupled into dimers by a dominant AFM intradimer interaction (J intra ), resulting in a spin-singlet ground state and gapped triplon excitations.…”

mentioning

confidence: 99%

“…This implies that the Cu 2+ ions are coupled into dimers by a dominant AFM intradimer interaction (J intra ), resulting in a spin-singlet ground state and gapped triplon excitations. The interdimer interaction (J inter ) was previously assumed to be AFM with strength between 0 % and 20 % of the intradimer coupling [25,[34][35][36][37].…”

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confidence: 99%

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Magnetic excitations in theS=12antiferromagnetic-ferromagnetic chain compoundBaCu2V2O

et al. 2016

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Unlike most quantum systems which rapidly become incoherent as temperature is raised, strong correlations persist at elevated temperatures in S = 1/2 dimer magnets, as revealed by the unusual asymmetric lineshape of their excitations at finite temperatures. Here we quantitatively explore and parameterize the strongly correlated magnetic excitations at finite temperatures using the high resolution inelastic neutron scattering on the model compound BaCu2V2O8 which we show to be an alternating antiferromagnetic-ferromagnetic spin−1/2 chain. Comparison to state of the art computational techniques shows excellent agreement over a wide temperature range. Our findings hence demonstrate the possibility to quantitatively predict coherent behavior at elevated temperatures in quantum magnets.In the study of unconventional states of matter, quantum magnetic materials with their strong correlations play a crucial role [1][2][3][4][5]. Quantum mechanical coherence and entanglement are intrinsic to these systems, both being relevant for potential applications in quantum devices [6,7]. However, the question arises for their persistence when increasing temperature. Intuitively, one expects temperature to suppress quantum behavior, as typically encountered in the study of quantum criticality [8]. Interestingly, this is not always the case, and in certain systems, e.g. in the presence of disorder, coherent behavior is not simply suppressed by temperature, but rather an interesting interplay develops [9,10], which can lead to counterintuitive behavior such as the increase of conductance through molecules with temperature [11].Another example is the extraordinary coherence of the magnetic excitations at elevated temperatures. This was theoretically predicted for 1-dimensional (1D) gapped quantum dimer antiferromagnets (AFM) by using integrable quantum field theory [12] and was experimentally confirmed on the strongly dimerized spin−1/2 AFM alternating chain compound copper nitrate, which has a spin-singlet ground state and gapped triplet excitations (henceforth referred to as triplons [13]) confined within a narrow band [14]. Here, the triplons interact strongly via the AFM interdimer coupling and also via an effective repulsive interaction due to the hard-core constraint. The resulting strong correlations lead to the experimentally observed asymmetric broadening of the lineshape with temperature [14,15]. So far, such experimental data was compared to exact diagonalization data from small systems and to results from low-temperature expansion around the strongly dimerized limit of Heisenberg spin-1/2 chains [16,17]. Further experimental studies revealed that the strongly correlated behavior at elevated temperatures is not restricted to 1D systems. It was recently observed that the lineshape in the 3-dimensional (3D) coupled-dimer antiferromagnet Sr 3 Cr 2 O 8 also becomes asymmetric and increasingly weighted towards the center of the band as temperature increases [18,19]. So far, no reliable theoretical approaches on the microscopic ...

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confidence: 68%

contrasting

confidence: 56%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Magnetic excitations in theS=12antiferromagnetic-ferromagnetic chain compoundBaCu2V2O

et al. 2016

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“…Strong quantum fluctuations due to low dimensionality may suppress the long-range magnetic ordering, resulting in an opening of a finite spin gap separated from the spin singlet ground state and magnetic excited states [3,4]. During the past decades, quantum spin systems such as SrCu 2 O 3 , BaCu 2 V 2 O 8 , CuTe 2 O 5 , Cu 2 Sc 2 Ge 4 O 13 , Cu 2 PO 4 OH, and BiCu 2 VO 6 have been discovered to possess spin gaps [5][6][7][8][9][10][11][12][13][14][15]. The spin gap characteristics have been interpreted in accordance with the strong spin exchange interactions of particular configurations along specific low-dimensional pathways in these materials [16,17].…”

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confidence: 99%