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Kühne, H.; Klauß, H.‐H.; Grossjohann, S.; Brenig, Wilhelm; Litterst, F. J.; Reyes, A. P.; Kuhns, P. L.; Turnbull, Mark M.; Landee, Christopher P.

doi:10.1103/physrevb.80.045110

Cited by 32 publications

(15 citation statements)

References 39 publications

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“…Figure 4(a) reproduces the temperature dependence of 13 C 1/T 1 in H = 13.80 T, taken from Ref. [35]. This field value corresponds to 0.94H s for the given orientation, i.e., H ⊥ a and 50…”

Section: (B)-2(d) Represents the Theoretical Scaling Function Eq (3)mentioning

confidence: 78%

“…The collapsed magnetization data closely follow the theoretical scaling function for a certain range, which allows us to draw experimental boundaries of the quantum critical region. Subsequently, we revisit the reported NMR relaxation data [35] to show that the spin dynamics close to H s display the theoretically predicted power-law behavior for a quantum critical region, up to rather high temperatures k B T J . [25] where they reported H s = 13.97(6) T. To test for quantum critical scaling, the data should be filtered such that those belonging to the neighboring TLL and ferromagnetic phases are excluded.…”

mentioning

confidence: 79%

“…• from b to c [35,43]. NMR 1/T 1 probes local electron spin correlations in the low energy limit, and a power-law behavior 1/T 1 ∝ T θ is expected for a gapless, quantum critical region [2,7,16].…”

Section: (B)-2(d) Represents the Theoretical Scaling Function Eq (3)mentioning

confidence: 99%

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Quantum critical scaling for a Heisenberg spin-12chain around saturation

Jeong

Rønnow

2015

Phys. Rev. B

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We demonstrate quantum critical scaling for an S = 1/2 Heisenberg antiferromagnetic chain compound Cu(C 4 H 4 N 2 )(NO 3 ) 2 in a magnetic field around saturation, by analyzing previously reported magnetization [Y. Kono et al., Phys. Rev. Lett. 114, 037202 (2015)], thermal expansion [J. Rohrkamp et al., J. Phys.: Conf. Ser. 200, 012169 (2010)], and NMR relaxation data [H. Kühne et al., Phys. Rev. B 80, 045110 (2009)]. The scaling of magnetization is demonstrated through collapsing the data for a range of both temperature and field onto a single curve without making any assumption for a theoretical form. The data collapse is subsequently shown to closely follow the theoretically predicted scaling function without any adjustable parameters. Experimental boundaries for the quantum critical region could be drawn from the variable range beyond which the scaled data deviate from the theoretical function. Similarly to the magnetization, quantum critical scaling of the thermal expansion is also demonstrated. Further, the spin dynamics probed via NMR relaxation rate 1/T 1 close to the saturation is shown to follow the theoretically predicted quantum critical behavior as 1/T 1 ∝ T −0.5 persisting up to temperatures as high as k B T J , where J is the exchange coupling constant. A quantum critical point (QCP) is a zero-temperature singularity in the phase diagram of matter forming the border between two competing ground states [1]. It is driven by a nonthermal parameter such as a magnetic field, pressure, or chemical substitution, and characterized by strong quantum fluctuations. While a QCP is defined strictly at zero temperature, the interplay between quantum and thermal fluctuations gives rise to a so-called quantum critical region at finite temperatures in an extended parameter space (illustrated by the yellow fan-out area in Fig. 1). This intriguing region is characterized by the absence of energy scales other than temperature as well as the corresponding critical properties of physical observables, e.g., correlation or response functions, which culminate into scaling behavior and universality [1][2][3][4]. Such quantum criticality has been experimentally observed or inferred in diverse systems including magnetic insulators [5][6][7], organic conductors [8], heavy fermions [9,10], cuprates [11], pnictides [12], and cold atoms [13], and is widely believed to underpin exotic phenomena like unconventional superconductivity. However, understanding quantum criticality through connecting microscopics to experimental observation largely remains challenging [1,[8][9][10][11][12]14].Quantum magnets are an ideal playground in that respect owing to their simple and well-defined Hamiltonian [15]. In particular, one-dimensional (1D) spin systems for which exact solutions are available may serve as a test bed for quantitative comparison between theories and experiments [16][17][18][19]. Indeed, quite a few excellent quasi-1D quantum magnets having accessible critical field strength, i.e., relatively small exchange coupling strengt...

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Section: (B)-2(d) Represents the Theoretical Scaling Function Eq (3)mentioning

confidence: 78%

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confidence: 79%

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Quantum critical scaling for a Heisenberg spin-12chain around saturation

Jeong

Rønnow

2015

Phys. Rev. B

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“…In spin chains near saturation, recent studies addressed the universality of thermodynamic properties [14][15][16] and quasistatic (low-frequency limit) correlation functions [15,17,18]. Unfortunately, the much-anticipated universality of finitetemperature dynamic spin correlations remained elusive to date due to unique technical challenges.…”

Section: Introductionmentioning

confidence: 99%

Finite-temperature correlations in a quantum spin chain near saturation

et al. 2017

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Inelastic neutron-scattering and finite-temperature density matrix renormalization group (DMRG) calculations are used to investigate the spin excitation spectrum of the S = 1/2 Heisenberg spin chain compound K 2 CuSO 4 Cl 2 at several temperatures in a magnetic field near saturation. Critical correlations characteristic of the predicted z = 2, d = 1 quantum phase transition occurring at saturation are shown to be consistent with the observed neutron spectra. The data is well described with a scaling function computed using a free fermion description of the spins, valid close to saturation, and the corresponding scaling limits. One of the most prominent nonuniversal spectral features of the data is a novel thermally activated longitudinal mode that remains underdamped across most of the Brillouin zone.

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“…From a materials perspective SrCuO 2 ͑J / k B Ϸ 2600 K͒, 1 Sr 2 CuO 3 ͑J / k B Ϸ 2200 K͒, [2][3][4] and Cu-͑C 4 H 4 N 2 ͒͑NO 3 ͒ 2 ͑J / k B Ϸ 10.7 K͒ 5 are topical examples of both low-J and high-J AFHC compounds which have been studied intensively. 6 Recently, dynamical correlation functions of the AFHC have become accessible to a variety of high-resolution spectroscopies at finite temperature and in the presence of external magnetic fields, e.g., inelastic neutron scattering ͑INS͒, 7 high-field nuclear magnetic resonance ͑NMR͒, [8][9][10][11] muon spin resonance ͑SR͒, 12 and magnetic transport. 13,14 The AFHC is integrable, including the cases of h 0 and ⌬ 1.…”

Section: Introductionmentioning

confidence: 99%

Spin dynamics of the antiferromagnetic spin-12chain at finite magnetic fields and intermediate temperatures

Grossjohann

Brenig

2009

Phys. Rev. B

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We present a study of the dynamic structure factor of the antiferromagnetic spin-1 2 Heisenberg chain at finite temperatures and finite magnetic fields. Using quantum Monte Carlo based on the stochastic series expansion and maximum entropy methods, we evaluate the longitudinal and the transverse dynamic structure factors from vanishing magnetic fields up to and above the threshold B c for ferromagnetic saturation, as well as for high and for intermediate temperatures. We study the field-induced redistribution of spectral weight contrasting longitudinal versus transverse excitations. At finite fields below saturation incommensurate low-energy modes are found consistent with zero-temperature Bethe ansatz. The crossover between the field-induced ferromagnet above B c and the Luttinger liquid below B c is analyzed in terms of the transverse spin dynamics. Evaluating sum rules we assess the quality of the analytic continuation and demonstrate excellent consistency of the maximum entropy results.

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Quantum critical dynamics of anS=12antiferromagnetic Heisenberg chain studied byC

Cited by 32 publications

References 39 publications

Quantum critical scaling for a Heisenberg spin-12chain around saturation

Quantum critical scaling for a Heisenberg spin-12chain around saturation

Finite-temperature correlations in a quantum spin chain near saturation

Spin dynamics of the antiferromagnetic spin-12chain at finite magnetic fields and intermediate temperatures

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