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Ediger MD, Gruebele M, Lubchenko V, Wolynes PG. Glass Dynamics Deep in the Energy Landscape. J Phys Chem B 2021; 125:9052-9068. [PMID: 34357766 DOI: 10.1021/acs.jpcb.1c01739] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
When a liquid is cooled, progress down the energy landscape is arrested near the glass transition temperature Tg. In principle, lower energy states can be accessed by waiting for further equilibration, but the rough energy landscape of glasses quickly leads to kinetics on geologically slow time scales below Tg. Over the past decade, progress has been made probing deeper into the energy landscape via several techniques. By looking at bulk and surface diffusion, using layered deposition that promotes equilibration, imaging glass surfaces with faster dynamics below Tg, and optically exciting glasses, experiments have moved into a regime of ultrastable, low energy glasses that was difficult to access in the past. At the same time, both simulations and energy landscape theory based on a random first order transition (RFOT) have tackled systems that include surfaces, optical excitation, and interfacial dynamics. Here we review some of the recent experimental work, and how energy landscape theory illuminates glassy dynamics well below the glass transition temperature by making direct connections between configurational entropy, energy landscape barriers, and the resulting dynamics.
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Affiliation(s)
- Mark D Ediger
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Martin Gruebele
- Department of Chemistry, Department of Physics, Center for Biophysics and Quantitative Biology, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, United States
| | - Vassiliy Lubchenko
- Departments of Chemistry and Physics, and the Center for Superconductivity, University of Houston, Houston, Texas 77204, United States
| | - Peter G Wolynes
- Departments of Chemistry, Physics and Astronomy, Biosciences, Materials Science and Nanoengineering, and the Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
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2
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Nguyen HA, Liao C, Wallum A, Lyding J, Gruebele M. Multi-scale dynamics at the glassy silica surface. J Chem Phys 2019; 151:174502. [PMID: 31703525 DOI: 10.1063/1.5123228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Silica-based glass is a household name, providing insulation for windows to microelectronics. The debate over the types of motions thought to occur in or on SiO2 glass well below the glass transition temperature continues. Here, we form glassy silica films by oxidizing the Si(100) surface (from 0.5 to 1.5 nm thick, to allow tunneling). We then employ scanning tunneling microscopy in situ to image and classify these motions at room temperature on a millisecond to hour time scale and 50-pm to 5-nm length scale. We observe two phenomena on different time scales. Within minutes, compact clusters with an average diameter of several SiO2 glass-forming units (GFUs) hop between a few (mostly two) configurations, hop cooperatively (facilitation), and merge into larger clusters (aging) or split into smaller clusters (rejuvenation). Within seconds, Si-O-Si bridges connect two GFUs within a single cluster flip, providing a vibrational fine structure to the energy landscape. We assign the vibrational fine structure using electronic structure calculations. Calculations also show that our measured barrier height for whole cluster hopping at the glass surface (configurational dynamics) is consistent with the configurational entropy predicted by thermodynamic models of the glass transition and that the vibrational entropy for GFU flipping and configurational entropy for cluster hopping are comparable (on a per GFU basis).
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Affiliation(s)
- Huy A Nguyen
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Can Liao
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Alison Wallum
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - J Lyding
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - M Gruebele
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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3
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Choe J, Lee Y, Park J, Kim Y, Kim CU, Kim K. Direct imaging of structural disordering and heterogeneous dynamics of fullerene molecular liquid. Nat Commun 2019; 10:4395. [PMID: 31562310 PMCID: PMC6765016 DOI: 10.1038/s41467-019-12320-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/04/2019] [Indexed: 11/10/2022] Open
Abstract
Structural rearrangements govern the various properties of disordered systems and visualization of these dynamical processes can provide critical information on structural deformation and phase transformation of the systems. However, direct imaging of individual atoms or molecules in a disordered state is quite challenging. Here, we prepare a model molecular system of C70 molecules on graphene and directly visualize the structural and dynamical evolution using aberration-corrected transmission electron microscopy. E-beam irradiation stimulates dynamics of fullerene molecules, which results in the first-order like structural transformation from the molecular crystal to molecular liquid. The real-time tracking of individual molecules using an automatic molecular identification process elucidates the relaxation behavior of a stretched exponential functional form. Moreover, the directly observed heterogeneous dynamics bear similarity to the dynamical heterogeneity in supercooled liquids near the glass transition. Fullerenes on graphene can serve as a new model system, which allows investigation of molecular dynamics in disordered phases.
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Affiliation(s)
- Jeongheon Choe
- Department of Physics, Yonsei University, Seoul, 03722, Korea.,Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Korea
| | - Yangjin Lee
- Department of Physics, Yonsei University, Seoul, 03722, Korea.,Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722, Korea
| | - Jungwon Park
- School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Seoul, 08826, Korea.,Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, 08826, Korea
| | - Yunho Kim
- Department of Mathematical Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Korea
| | - Chae Un Kim
- Department of Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Korea.
| | - Kwanpyo Kim
- Department of Physics, Yonsei University, Seoul, 03722, Korea. .,Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722, Korea.
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4
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Wingert MC, Kwon S, Cai S, Chen R. Fluid-like Surface Layer and Its Flow Characteristics in Glassy Nanotubes. NANO LETTERS 2016; 16:7545-7550. [PMID: 27798834 DOI: 10.1021/acs.nanolett.6b03377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We show that amorphous silica and Si nanotubes can flow at room temperature under Giga-Pascal order stress when going to the nanometer scale. This creep behavior is unique for the amorphous nanotubes and is absent in crystalline Si nanotubes of similar dimensions. A core-shell model shows that there exists an approximately 1 nm thick viscoelastic "fluid-like" surface layer, which exhibits a room temperature viscosity equivalent to that of bulk glass above 1000 °C.
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Affiliation(s)
- Matthew C Wingert
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Soonshin Kwon
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Shengqiang Cai
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
| | - Renkun Chen
- Department of Mechanical and Aerospace Engineering, University of California, San Diego , La Jolla, California 92093, United States
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5
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Guseva DV, Chertovich AV, Rudyak VY. Systematic study of glass transition in low-molecular phthalonitriles: Insight from computer simulations. J Chem Phys 2016; 145:144503. [PMID: 27782502 DOI: 10.1063/1.4964616] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- D. V. Guseva
- Department of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - A. V. Chertovich
- Department of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
| | - V. Yu. Rudyak
- Department of Physics, Lomonosov Moscow State University, Moscow 119991, Russia
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6
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Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films. Sci Rep 2016; 6:30973. [PMID: 27498698 PMCID: PMC4976322 DOI: 10.1038/srep30973] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 07/12/2016] [Indexed: 11/24/2022] Open
Abstract
Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100−xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections.
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Nguyen D, Zhu ZG, Pringle B, Lyding J, Wang WH, Gruebele M. Composition-dependent metallic glass alloys correlate atomic mobility with collective glass surface dynamics. Phys Chem Chem Phys 2016; 18:16856-61. [PMID: 27283239 DOI: 10.1039/c6cp02654k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Glassy metallic alloys are richly tunable model systems for surface glassy dynamics. Here we study the correlation between atomic mobility, and the hopping rate of surface regions (clusters) that rearrange collectively on a minute to hour time scale. Increasing the proportion of low-mobility copper atoms in La-Ni-Al-Cu alloys reduces the cluster hopping rate, thus establishing a microscopic connection between atomic mobility and dynamics of collective rearrangements at a glass surface made from freshly exposed bulk glass. One composition, La60Ni15Al15Cu10, has a surface resistant to re-crystallization after three heating cycles. When thermally cycled, surface clusters grow in size from about 5 glass-forming units to about 8 glass-forming units, evidence of surface aging without crystal formation, although its bulk clearly forms larger crystalline domains. Such kinetically stable glass surfaces may be of use in applications where glassy coatings stable against heating are needed.
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Affiliation(s)
- Duc Nguyen
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. and Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA
| | - Zhi-Guang Zhu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Brian Pringle
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA.
| | - Joseph Lyding
- Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA and Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801, USA
| | - Wei-Hua Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Martin Gruebele
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. and Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA and Department of Physics, University of Illinois, Urbana, Illinois 61801, USA
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8
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Nguyen D, Mallek J, Cloud AN, Abelson JR, Girolami GS, Lyding J, Gruebele M. The energy landscape of glassy dynamics on the amorphous hafnium diboride surface. J Chem Phys 2014; 141:204501. [DOI: 10.1063/1.4901132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Duc Nguyen
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Justin Mallek
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Andrew N. Cloud
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - John R. Abelson
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Gregory S. Girolami
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Joseph Lyding
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Martin Gruebele
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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9
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Abstract
Abstract
Focusing on metallic glasses as model systems, we review the features and mechanisms of the β-relaxations, which are intrinsic and universal to supercooled liquids and glasses, and demonstrate their importance in understanding many crucial unresolved issues in glassy physics and materials science, including glass transition phenomena, mechanical properties, shear-banding dynamics and deformation mechanisms, diffusion and the breakdown of the Stokes–Einstein relation as well as crystallization and stability of glasses. We illustrate that it is an attractive prospect to incorporate these insights into the design of new glassy materials with extraordinary properties. We also outline important questions regarding the nature of β-relaxations and highlight some emerging research directions in this still-evolving field.
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Affiliation(s)
- Hai Bin Yu
- Physikalisches Institut, Universität Göttingen, D-37077 Göttingen, Germany
| | - Wei Hua Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hai Yang Bai
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Konrad Samwer
- Physikalisches Institut, Universität Göttingen, D-37077 Göttingen, Germany
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10
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Liu X, Queen DR, Metcalf TH, Karel JE, Hellman F. Hydrogen-free amorphous silicon with no tunneling states. PHYSICAL REVIEW LETTERS 2014; 113:025503. [PMID: 25062205 DOI: 10.1103/physrevlett.113.025503] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 05/14/2023]
Abstract
The ubiquitous low-energy excitations, known as two-level tunneling systems (TLSs), are one of the universal phenomena of amorphous solids. Low temperature elastic measurements show that e-beam amorphous silicon (a-Si) contains a variable density of TLSs which diminishes as the growth temperature reaches 400 °C. Structural analyses show that these a-Si films become denser and more structurally ordered. We conclude that the enhanced surface energetics at a high growth temperature improved the amorphous structural network of e-beam a-Si and removed TLSs. This work obviates the role hydrogen was previously thought to play in removing TLSs in the hydrogenated form of a-Si and suggests it is possible to prepare "perfect" amorphous solids with "crystal-like" properties for applications.
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Affiliation(s)
- Xiao Liu
- Naval Research Laboratory, Code 7130, Washington, D.C. 20375, USA
| | - Daniel R Queen
- NRC Postdoctoral Associate, Naval Research Laboratory, Washington, D.C. 20375, USA
| | - Thomas H Metcalf
- Naval Research Laboratory, Code 7130, Washington, D.C. 20375, USA
| | - Julie E Karel
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA
| | - Frances Hellman
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA and Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, California 94720, USA
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11
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Queen DR, Liu X, Karel J, Metcalf TH, Hellman F. Excess specific heat in evaporated amorphous silicon. PHYSICAL REVIEW LETTERS 2013; 110:135901. [PMID: 23581344 DOI: 10.1103/physrevlett.110.135901] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 01/02/2013] [Indexed: 06/02/2023]
Abstract
The specific heat C of e-beam evaporated amorphous silicon (a-Si) thin films prepared at various growth temperatures T(S) and thicknesses t was measured from 2 to 300 K, along with sound velocity v, shear modulus G, density n(Si), and Raman spectra. Increasing T(S) results in a more ordered amorphous network with increases in n(Si), v, G, and a decrease in bond angle disorder. Below 20 K, an excess C is seen in films with less than full density where it is typical of an amorphous solid, with both a linear term characteristic of two-level systems (TLS) and an additional (non-Debye) T3 contribution. The excess C is found to be independent of the elastic properties but to depend strongly on density. The density dependence suggests that low energy glassy excitations can form in a-Si but only in microvoids or low density regions and are not intrinsic to the amorphous silicon network. A correlation is found between the density of TLS n0 and the excess T3 specific heat c(ex) suggesting that they have a common origin.
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Affiliation(s)
- D R Queen
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA
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12
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Angell CA, Zhao Z. Fluctuations, clusters, and phase transitions in liquids, solutions, and glasses: from metastable water to phase change memory materials. Faraday Discuss 2013; 167:625-41. [DOI: 10.1039/c3fd00111c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Ashtekar S, Lyding J, Gruebele M. Temperature-dependent two-state dynamics of individual cooperatively rearranging regions on a glass surface. PHYSICAL REVIEW LETTERS 2012; 109:166103. [PMID: 23215096 DOI: 10.1103/physrevlett.109.166103] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/04/2012] [Indexed: 06/01/2023]
Abstract
Cooperatively rearranging regions (CRRs) play a central role in the temperature dependence of glass dynamics. We record real-time atomic resolution movies of individual CRRs, while ramping their temperature. Between 295 and 326 K, well below the bulk glass transition temperature T(g), the rate coefficient for two-state hopping of CRRs increases over tenfold, yielding an Arrhenius activation barrier of ≈10k(B)T(g). By time resolving the dynamics of many individual CRRs, we show that highly stretched dynamics of the CRR ensemble results mainly from spatial heterogeneity, less from temporal heterogeneity of individual CRRs.
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Affiliation(s)
- S Ashtekar
- Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois 61801, USA
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14
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Ashtekar S, Nguyen D, Zhao K, Lyding J, Wang WH, Gruebele M. Communication: An obligatory glass surface. J Chem Phys 2012; 137:141102. [DOI: 10.1063/1.4757975] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Garcez KMS, Antonelli A. Pressure effects on the transitions between disordered phases in supercooled liquid silicon. J Chem Phys 2011; 135:204508. [DOI: 10.1063/1.3663387] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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