Low-temperature properties of crystalline (KBr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi mathvariant="normal">−</mml:mi><mml:mi mathvariant="normal">x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>(KCN<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mi mathvariant="normal">x</mml

Yoreo, James J. De; Knaak, W.; Meissner, M.; Pohl, Robert Wichard

doi:10.1103/physrevb.34.8828

Cited by 136 publications

(55 citation statements)

References 47 publications

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“…Note that the T 3 terms are almost identical, suggesting that there is no additional T 3 term in the insulating sample coming from the presence of two-levelsystems [36]. Intriguingly, the γ term does not change significantly across the metal-insulator transition (γ met ≈ 2γ ins ).…”

Section: Discussionmentioning

confidence: 95%

Thermal conductivity across the metal-insulator transition in the single-crystalline hyperkagome antiferromagnetNa3+xIr3O8

Fauqué

Bangura

et al. 2015

Phys. Rev. B

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The hyperkagome antiferromagnet Na 4 Ir 3 O 8 represents the first genuine candidate for the realization of a three-dimensional quantum spin liquid. It can also be doped towards a metallic state, thus offering a rare opportunity to explore the nature of the metal-insulator transition in correlated, frustrated magnets. Here, we report thermodynamic and transport measurements in both metallic and weakly insulating single crystals down to 150 mK. While in the metallic sample the phonon thermal conductivity (κ ph ) is almost in the boundary scattering regime, in the insulating sample, we find a large reduction κ ph over a very wide temperature range. This result can be ascribed to the scattering of phonons off the gapless magnetic excitations that are seen in the low-temperature specific heat. This works highlights the peculiarity of the metal-insulator transition in Na 3+x Ir 3 O 8 and demonstrates the importance of the coupling between lattice and spin degrees of freedom in the presence of strong spin-orbit coupling.

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Section: Discussionmentioning

confidence: 95%

Thermal conductivity across the metal-insulator transition in the single-crystalline hyperkagome antiferromagnetNa3+xIr3O8

Fauqué

Bangura

et al. 2015

Phys. Rev. B

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“…A heat capacity contribution from the calorimeter (including a thin film W-heater and resistance 35 Tg is sometimes substituted by the "dipolar freezing temperature"). (2) Tetrahedrally bounded glass system AsxSe1-x (x ) 0-0.5).…”

Section: Methodsmentioning

confidence: 99%

Low-Temperature Heat Capacity, Glass-Transition Cooperativity, and Glass-Structure Vault Breakdown in a Series of Poly(n-alkyl methacrylate)s

Beiner¹,

Kahle²,

Abens³

et al. 2001

Macromolecules

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Heat capacity in the 1 K range and close to Tg was studied in a series of poly(n-alkyl methacrylate)s, PnAMA, including some random copolymers. We report on two findings: (i) The glass transition temperature Tg and the cooperativity of the R process that freezes-in at Tg, NR(Tg), decrease smoothly between methyl (PMMA) and hexyl member (PnHMA); the cooperativity from NR(Tg) ) 35 to NR(Tg) ≈ 1. (ii) The tunnel density measured in the 1 K range as c1 constant of the heat capacity function increases between PMMA and the ethyl member (PEMA), shows, after a maximum near PEMA, a sharp drop (factor of 6) to the butyl member (PnBMA), and remains constant at a low level up to the octyl member (PnOMA). The cooperativity of the R process near Tg and the tunnel density will be correlated assuming that freezing-in (vitrification) fixes the dynamic heterogeneity in the self-organized equilibrium liquid near Tg. We try to explain how freezing of dynamic heterogeneities in the PnAMA series is responsible for the trend in the tunnel density including the sharp drop: Freezing-in of cooperativity shells around Glarum defects forms some vaults that enlarge the free volume near these defects in comparison to a situation without vaults. The maximum in c1 is promoted by this additional free volume; the drop in c1 is caused by a vault breakdown effect if the cooperativity shell is too small for vault formation, NR(Tg) < 15.

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“…Detailed studies on the entities executing such tunneling motions were carried out on mixed crystals allowing to identify the microscopic entities executing such motions. 8 In contrast, work concerning structural glasses can only be carried out on phenomenological grounds and no widely accepted answers concerning the identity of particles executing such motions have been given. The thermal properties of glassy matter at low temperature such as the rise up of C p /T 3 as the temperature decreases or the presence of a plateau in the thermal conductivity have been considered as a glaring evidence of universal behaviour, and are usually modeled by recourse to the tunneling model.…”

Section: Introductionmentioning

confidence: 97%

Glassy Dynamics versus Thermodynamics: The Case of 2-Adamantanone

Szewczyk¹,

Jeżowski²,

Vdovichenko

et al. 2015

J. Phys. Chem. B

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The heat capacity and thermal conductivity of the monoclinic and the fully ordered orthorhombic phases of 2-adamantanone (C10H14O) have been measured for temperatures between 2 and 150 K. The heat capacities for both phases are shown to be strikingly close regardless of the site disorder present in the monoclinic crystal which arises from the occupancy of three nonequivalent sites for the oxygen atom. The heat capacity curves are also well accounted for by an evaluation carried out within the harmonic approximation in terms of the g(ω) vibrational frequency distributions measured by means of inelastic neutron scattering. Such spectral functions show however a significant excess of low frequency modes for the crystal showing statistical disorder. In contrast, large differences are found for the thermal conductivity which contrary to what could be expected, shows the substitutionally disordered crystal to exhibit better heat transport properties than the fully ordered orthorhombic phase. Such an anomalous behavior is understood from examination of the crystalline structure of the orthorhombic phase which leads to very strong scattering of heat-carrying phonons due to grain boundary effects able to yield a largely reduced value of the conductivity as well as to a plateau-like feature at intermediate temperatures which contrasts with a bell-shaped maximum shown by data pertaining the disordered crystal. The relevance of the present findings within the context of glassy dynamics of the orientational glass state is finally discussed.

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Low-temperature properties of crystalline (KBr)1−x(KCN)x

Cited by 136 publications

References 47 publications

Thermal conductivity across the metal-insulator transition in the single-crystalline hyperkagome antiferromagnetNa3+xIr3O8

Thermal conductivity across the metal-insulator transition in the single-crystalline hyperkagome antiferromagnetNa3+xIr3O8

Low-Temperature Heat Capacity, Glass-Transition Cooperativity, and Glass-Structure Vault Breakdown in a Series of Poly(n-alkyl methacrylate)s

Glassy Dynamics versus Thermodynamics: The Case of 2-Adamantanone

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