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Zheng Q, Mauro JC. Variability in the relaxation behavior of glass: Impact of thermal history fluctuations and fragility. J Chem Phys 2017; 146:074504. [DOI: 10.1063/1.4975760] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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Micoulaut M. Relaxation and physical aging in network glasses: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:066504. [PMID: 27213928 DOI: 10.1088/0034-4885/79/6/066504] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Recent progress in the description of glassy relaxation and aging are reviewed for the wide class of network-forming materials such as GeO2, Ge x Se1-x , silicates (SiO2-Na2O) or borates (B2O3-Li2O), all of which have an important usefulness in domestic, geological or optoelectronic applications. A brief introduction of the glass transition phenomenology is given, together with the salient features that are revealed both from theory and experiments. Standard experimental methods used for the characterization of the slowing down of the dynamics are reviewed. We then discuss the important role played by aspects of network topology and rigidity for the understanding of the relaxation of the glass transition, while also permitting analytical predictions of glass properties from simple and insightful models based on the network structure. We also emphasize the great utility of computer simulations which probe the dynamics at the molecular level, and permit the calculation of various structure-related functions in connection with glassy relaxation and the physics of aging which reveal the non-equilibrium nature of glasses. We discuss the notion of spatial variations of structure which leads to the concept of 'dynamic heterogeneities', and recent results in relation to this important topic for network glasses are also reviewed.
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Affiliation(s)
- Matthieu Micoulaut
- Paris Sorbonne Universités, LPTMC-UPMC, 4 place Jussieu, 75252 Paris cedex 05, France
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Pacaud F, Micoulaut M. Thermodynamic precursors, liquid-liquid transitions, dynamic and topological anomalies in densified liquid germania. J Chem Phys 2015; 143:064502. [DOI: 10.1063/1.4927707] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Densified network glasses and liquids with thermodynamically reversible and structurally adaptive behaviour. Nat Commun 2015; 6:6398. [DOI: 10.1038/ncomms7398] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/25/2015] [Indexed: 11/08/2022] Open
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Micoulaut M, Bauchy M, Flores-Ruiz H. Topological Constraints, Rigidity Transitions, and Anomalies in Molecular Networks. MOLECULAR DYNAMICS SIMULATIONS OF DISORDERED MATERIALS 2015. [DOI: 10.1007/978-3-319-15675-0_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Bauchy M, Kachmar A, Micoulaut M. Structural, dynamic, electronic, and vibrational properties of flexible, intermediate, and stressed rigid As-Se glasses and liquids from first principles molecular dynamics. J Chem Phys 2014; 141:194506. [DOI: 10.1063/1.4901515] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- M. Bauchy
- Department of Civil and Environmental Engineering, University of California, Los Angeles, California 90095-1593, USA
| | - A. Kachmar
- Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie, 4 Place Jussieu, F-75252 Paris Cedex 05, France
- Qatar Environment and Energy Research Institute, Qatar Foundation, P.O. Box 5825, Doha, Qatar
| | - M. Micoulaut
- Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie, 4 Place Jussieu, F-75252 Paris Cedex 05, France
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Hermansen C, Mauro JC, Yue Y. A model for phosphate glass topology considering the modifying ion sub-network. J Chem Phys 2014. [DOI: 10.1063/1.4870764] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ravindren S, Gunasekera K, Tucker Z, Diebold A, Boolchand P, Micoulaut M. Crucial effect of melt homogenization on the fragility of non-stoichiometric chalcogenides. J Chem Phys 2014; 140:134501. [DOI: 10.1063/1.4869107] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Chakraborty S, Boolchand P. Topological origin of fragility, network adaptation, and rigidity and stress transitions in especially homogenized nonstoichiometric binary Ge(x)S(100-x) glasses. J Phys Chem B 2014; 118:2249-63. [PMID: 24471439 DOI: 10.1021/jp411823j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Binary GexS100-x glasses reveal a richness of elastic and chemical phase transitions driven by network topology. With increasing Ge content (x), well-defined rigidity at xc(1) = 19.3(5)% and a stress transition at xc(2) = 24.9(5)% are observed in Raman scattering. In modulated DSC measurements, the nonreversing enthalpy of relaxation at Tg reveals a square-well-like minimum (reversibility window) with window walls that coincide with the two elastic phase transitions. Molar volumes show a trapezoidal-like minimum (volumetric window) with edges that nearly coincide with the reversibility window. These optical, thermal, and volumetric results are consistent with an isostatically rigid elastic phase (intermediate phase, IP) present between the rigidity (xc(1)) and stress (xc(2)) transitions. Complex Cp measurements show melt fragility index, m(x) to also show a global minimum in the reversibility window with m < 20, underscoring that melt dynamics encode the elastic behavior of the glass formed at Tg. The strong nature of melts formed in the IP has an important practical consequence; they lead to slow homogenization (over days not hours) of nonstoichiometric Ge-S batch compositions reacted at high temperatures. Homogenization of chalcogenide melts/glasses over a scale of a few micrometers is a prerequisite to observe the intrinsic physical properties of these materials.
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Affiliation(s)
- Shibalik Chakraborty
- Department of Electronic and Computing Systems, College of Engineering and Applied Science, University of Cincinnati , Cincinnati, Ohio 45220-0030, United States
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Chakraborty S, Boolchand P, Malki M, Micoulaut M. Designing heavy metal oxide glasses with threshold properties from network rigidity. J Chem Phys 2014; 140:014503. [DOI: 10.1063/1.4855695] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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Gunasekera K, Bhosle S, Boolchand P, Micoulaut M. Superstrong nature of covalently bonded glass-forming liquids at select compositions. J Chem Phys 2013; 139:164511. [DOI: 10.1063/1.4826463] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bauchy M, Micoulaut M, Boero M, Massobrio C. Compositional thresholds and anomalies in connection with stiffness transitions in network glasses. PHYSICAL REVIEW LETTERS 2013; 110:165501. [PMID: 23679615 DOI: 10.1103/physrevlett.110.165501] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Indexed: 06/02/2023]
Abstract
The structural and dynamical properties of amorphous and liquid As(x)Se(1-x) (0.2<x<0.4) are studied by first principles molecular dynamics. Within the above range of compositions, thresholds and anomalies are found in the behavior of reciprocal space properties that can be correlated to the experimental location of the so-called Boolchand intermediate phase in these glassy networks. These findings are associated with diffusion anomalies for the parent liquid phase, thereby linking structural and dynamical atomic-scale fingerprints for the onset of rigidity within the network, while also providing a much more complex picture than the one derived from mean-field approaches of stiffness transitions.
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Affiliation(s)
- M Bauchy
- Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie, 4 Place Jussieu, F-75252 Paris Cedex 05, France
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Bauchy M, Micoulaut M. Transport anomalies and adaptative pressure-dependent topological constraints in tetrahedral liquids: evidence for a reversibility window analogue. PHYSICAL REVIEW LETTERS 2013; 110:095501. [PMID: 23496720 DOI: 10.1103/physrevlett.110.095501] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Indexed: 06/01/2023]
Abstract
Topological rigid constraints can be computed rather simply with changing composition and temperature but their estimation remains challenging for other thermodynamic variables. Here, the investigation of densified silicate liquids from molecular dynamics simulations combined with an analysis of radial and angular atomic excursions allows defining a pressure dependence of such constraints. Results show, that for a given composition, the dependence is nonmonotonic as it depends on the interplay between constraints broken by thermal activation and additional constraints arising from the increase of network connectivity under pressure. An anomalous behavior for oxygen bending constraints is obtained in the (P, T) map which connects to reported anomalies in transport properties and is identified as the pressure analogue of the stress-free Boolchand intermediate phase in rigidity driven by composition.
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Affiliation(s)
- M Bauchy
- Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie, 4 Place Jussieu, F-75252 Paris Cedex 05, France
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Lencer D, Salinga M, Wuttig M. Design rules for phase-change materials in data storage applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:2030-2058. [PMID: 21469218 DOI: 10.1002/adma.201004255] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Indexed: 05/30/2023]
Abstract
Phase-change materials can rapidly and reversibly be switched between an amorphous and a crystalline phase. Since both phases are characterized by very different optical and electrical properties, these materials can be employed for rewritable optical and electrical data storage. Hence, there are considerable efforts to identify suitable materials, and to optimize them with respect to specific applications. Design rules that can explain why the materials identified so far enable phase-change based devices would hence be very beneficial. This article describes materials that have been successfully employed and dicusses common features regarding both typical structures and bonding mechanisms. It is shown that typical structural motifs and electronic properties can be found in the crystalline state that are indicative for resonant bonding, from which the employed contrast originates. The occurence of resonance is linked to the composition, thus providing a design rule for phase-change materials. This understanding helps to unravel characteristic properties such as electrical and thermal conductivity which are discussed in the subsequent section. Then, turning to the transition kinetics between the phases, the current understanding and modeling of the processes of amorphization and crystallization are discussed. Finally, present approaches for improved high-capacity optical discs and fast non-volatile electrical memories, that hold the potential to succeed present-day's Flash memory, are presented.
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Affiliation(s)
- Dominic Lencer
- I. Physikalisches Institut IA, RWTH Aachen University, Germany
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Micoulaut M, Malki M. Direct evidence of a characteristic length scale of a dynamical nature in the Boolchand phase of glasses. PHYSICAL REVIEW LETTERS 2010; 105:235504. [PMID: 21231480 DOI: 10.1103/physrevlett.105.235504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Indexed: 05/30/2023]
Abstract
The ac conductivity spectra of xAgI-(1 - x)AgPO(3) fast-ion conducting glasses spanning the flexible, intermediate (isostatically rigid), and stressed rigid phases are analyzed. The rescaled frequency-dependent spectra are mapped into time-dependent mean-square displacements out of which a typical length scale characterizing the spatial extent sqrt[(R(2)(∞))] of nonrandom subdiffusive regions of ionic motions is computed. The latter quantity is studied as a function of AgI compositions, and is found to display a maximum isostatic compositions, providing the first clear evidence of a typical length scale of a dynamical nature when a system becomes isostatically rigid and enters that phase.
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Affiliation(s)
- M Micoulaut
- Laboratoire de Physique Théorique de la Matière Condensée, Université Pierre et Marie Curie, CNRS UMR 7600, Boite 121, 4, Place Jussieu, 75252 Paris Cedex 05, France
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