01745nas a2200169 4500008004100000022001400041245009700055210006900152260000800221300001100229490000800240520113000248100001801378700002401396700003401420856012101454 2022 eng d a2470-004500aIdentifying structural signature of dynamical heterogeneity via the local softness parameter0 aIdentifying structural signature of dynamical heterogeneity via  cAPR a0446040 v1053 a

In this work we study the relationship between the softness of a mean-field caging potential and dynamics at the local level. We first describe the local softness, which shows a distribution, thus identifying structural heterogeneity. We show that the lifetime of the softness parameter is connected to the lifetime of the well-known cage structure in supercooled liquids. Finally, our theory predicts that the local softness and the local dynamics is causal below the onset temperature where there is a decoupling between the short and long time dynamics, thus allowing a static description of the cage. With the decrease in temperature, the correlation between structure and dynamics increases. The study shows that at lower temperatures, the structural heterogeneity increases, and since the structure becomes a better predictor of the dynamics, it leads to an increase in the dynamical heterogeneity. We also find that the softness of a hard, immobile region evolves with time and becomes soft and eventually mobile due to the rearrangements in the neighborhood, confirming the well-known facilitation effect.

1 aSharma, Mohit1 aNandi, Manoj, Kumar1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/identifying-structural-signature-dynamical-heterogeneity-local-softness-parameter02356nas a2200157 4500008004100000022001400041245014500055210006900200260000900269490000800278520170500286100001801991700002402009700003402033856013102067 2023 eng d a0021-960600a Comparative study of the correlation between the structure and the dynamics for systems interacting via attractive and repulsive potentials0 aComparative study of the correlation between the structure and t cSEP 0 v1593 a

We present the study of the structure-dynamics correlation for systems interacting via attractive Lennard-Jones (LJ) and its repulsive counterpart, the Weeks-Chandler-Andersen (WCA) potentials. The structural order parameter (SOP) is related to the microscopic mean-field caging potential. At a particle level, the SOP shows a distribution. Although the two systems have similar pair structures, their average SOP differs. However, this difference alone is insufficient to explain the well known slowing down of the dynamics in the LJ system at low temperatures. The slowing down can be explained in terms of a stronger coupling between the SOP and the dynamics. To understand the origin of this system specific coupling, we study the difference in the microscopic structure between the hard and soft particles. We find that for the LJ system, the structural differences of the hard and soft particles are more significant and have a much stronger temperature dependence compared to the WCA system. Thus, the study suggests that attractive interaction creates more structurally different communities. This broader difference in the structural communities is probably responsible for stronger coupling between the structure and dynamics. Thus, the system specific structure-dynamics correlation, which also leads to a faster slowing down in the dynamics, appears to have a structural origin. A comparison of the predictive power of our SOP with the local energy and two body excess entropy in determining the dynamics shows that in the LJ system, the enthalpy plays a dominant role and in the WCA system, the entropy plays a dominant role, and our SOP can capture both these contributions.

1 aSharma, Mohit1 aNandi, Manoj, Kumar1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/comparative-study-correlation-between-structure-and-dynamics-systems-interacting-attractive02198nas a2200169 4500008004100000022001400041245013700055210006900192260000800261300001100269490000800280520154300288100001701831700001801848700003401866856012801900 2023 eng d a0021-960600aDynamic heterogeneity in polydisperse systems: a comparative study of the role of local structural order parameter and particle size0 aDynamic heterogeneity in polydisperse systems a comparative stud cJUL a0445010 v1593 a

In polydisperse systems, describing the structure and any structural order parameter (SOP) is not trivial as it varies with the number of species we use to describe the system, M. Depending on the degree of polydispersity, there is an optimum value of M = M-0 where we show that the mutual information of the system increases. However, surprisingly, the correlation between a recently proposed SOP and the dynamics is highest for M = 1. This effect increases with polydispersity. We find that the SOP at M = 1 is coupled with the particle size, s, and this coupling increases with polydispersity and decreases with an increase in M. Careful analysis shows that at lower polydispersities, the SOP is a good predictor of the dynamics. However, at higher polydispersity, the dynamics is strongly dependent on s. Since the coupling between the SOP and s is higher for M = 1, it appears to be a better predictor of the dynamics. We also study the Vibrality, an order parameter independent of structural information. Compared to SOP, at high polydispersity, we find Vibrality to be a marginally better predictor of the dynamics. However, this high predictive power of Vibrality, which is not there at lower polydispersity, appears to be due to its stronger coupling with s. Therefore, our study suggests that for systems with high polydispersity, the correlation of any order parameter and s will affect the correlation between the order parameter and dynamics and need not project a generic predictive power of the order parameter.

1 aPatel, Palak1 aSharma, Mohit1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/dynamic-heterogeneity-polydisperse-systems-comparative-study-role-local-structural-order02306nas a2200181 4500008004100000022001400041245013100055210006900186260000800255300001100263490000800274520162500282100002001907700001701927700001801944700003401962856012801996 2024 eng d a0021-960600aExploring the soft pinning effect in the dynamics and the structure-dynamics correlation in multicomponent supercooled liquids0 aExploring the soft pinning effect in the dynamics and the struct cOCT a1545010 v1613 a

We study multicomponent liquids by increasing the mass of 15% of the particles in a binary Kob-Andersen model. We find that the heavy particles have dual effects on the lighter particles. At higher temperatures, there is a significant decoupling of the dynamics between heavier and lighter particles, with the former resembling a pinned particle to the latter. The dynamics of the lighter particles slow down due to the excluded volume around the nearly immobile heavier particles. Conversely, at lower temperatures, there is a coupling between the dynamics of the heavier and lighter particles. The heavier particles' mass slows down the dynamics of both types of particles. This makes the soft pinning effect of the heavy particles questionable in this regime. We demonstrate that as the mass of the heavy particles increases, the coupling of the dynamics between the lighter and heavier particles weakens. Consequently, the heavier the mass of the heavy particles, the more effectively they act as soft pinning centers in both high and low-temperature regimes. A key finding is that akin to the pinned system, the self-dynamics and collective dynamics of the lighter particles decouple from each other as the mass of the heavy particles has a more pronounced impact on the latter. We analyze the structure-dynamics correlation by considering the system under the binary and modified quaternary framework, the latter describing the pinned system. Our findings indicate that whenever the heavy mass particles function as soft pinning centers, the modified quaternary framework predicts a higher correlation.

1 aAnwar, Ehtesham1 aPatel, Palak1 aSharma, Mohit1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/exploring-soft-pinning-effect-dynamics-and-structure-dynamics-correlation-multicomponent00715nas a2200229 4500008004100000022001400041245006700055210006700122260000900189490000800198653001600206653000900222653002100231653001000252653000900262100002200271700001800293700001800311700003400329700002600363856009600389 2024 eng d a0027-842400aStructural origin of relaxation in dense colloidal suspensions0 aStructural origin of relaxation in dense colloidal suspensions cOCT 0 v12110aDEFORMATION10aflow10aglass-transition10aORDER10aSOFT1 aSahu, Ratimanasee1 aSharma, Mohit1 aSchall, Peter1 aBhattacharyya, Sarika, Maitra1 aChikkadi, Vijayakumar uhttps://library.ncl.res.in/content/structural-origin-relaxation-dense-colloidal-suspensions02411nas a2200193 4500008004100000022001400041245009700055210006900152260000900221300001100230490000800241520173100249100002001980700001802000700002502018700001802043700003402061856012202095 2025 eng d a0021-960600aGrowth of structural lengthscale in Kob-Andersen binary mixtures: Role of medium range order0 aGrowth of structural lengthscale in KobAndersen binary mixtures  cNOV  a2045050 v1633 a

A central and extensively debated question in glass physics concerns whether a single, growing lengthscale fundamentally controls glassy dynamics, particularly in systems lacking obvious structural motifs such as the Kob-Andersen binary Lennard-Jones (KALJ) model. In this work, we investigate structural and dynamical lengthscales in supercooled liquids using the KALJ model in two compositions: 80:20 and 60:40. We compute the dynamical lengthscale from displacement-displacement correlation functions and observe a consistent growth as temperature decreases. To explore the static counterpart, we use a structural order parameter (SOP) based on the mean field caging potential. While this SOP is known to predict short time dynamics effectively, its bare correlation function reveals minimal spatial growth. Motivated by recent findings that long time dynamics reflect collective rearrangements, we perform spatial coarse-graining of the SOP and identify an optimal lengthscale L-max that maximizes structure-dynamics correlation. We show that the structural correlation length derived from SOP coarse-grained over L-max exhibits clear growth with cooling and closely tracks the dynamical lengthscale, especially for A particles in the 80:20 mixture and for both A and B particles in the 60:40 system. Our results reconcile the previously observed absence of static length growth in the KALJ model by highlighting the necessity of intermediate range structural descriptors. Furthermore, we find that the particles with larger structural length growth also correspond to species with latent crystallization tendencies, suggesting a possible link between structural order, dynamics, and incipient crystallization.

1 aKumawat, Sanket1 aSharma, Mohit1 aNandi, Ujjwal, Kumar1 aTah, Indrajit1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/growth-structural-lengthscale-kob-andersen-binary-mixtures-role-medium-range-order02638nas a2200229 4500008004100000022001400041245008700055210006900142260000900211300001100220490000900231520187900240653003002119653001202149653002002161653002002181653001502201100001802216700002102234700003402255856011902289 2025 eng d a1742-546800aStructure-dynamics correlation and its link to fragility and dynamic heterogeneity0 aStructuredynamics correlation and its link to fragility and dyna cSEP  a0940050 v20253 a

Understanding the connection between structure, dynamics, and fragility, the rate at which the relaxation time grows with the decreasing temperature, is central to unravelling the glass transition. Fragility is often associated with dynamic heterogeneity, implying that if the structure influences the dynamics, more fragile systems should exhibit stronger structure-dynamics correlations. In this study, we test the generality of this assumption using the Lennard-Jones (LJ) and Weeks-Chandler-Andersen systems, where the fragility is tuned via the density, and a modified LJ (q, p) system, where the fragility is varied by changing the potential softness. We define a structural order parameter based on a mean-field caging potential and analyse the energy barriers at both the macroscopic and microscopic levels. While the macroscopic free energy barrier slope correlates with fragility, the microscopic free energy barrier does not show a consistent trend. Instead, it exhibits a strong correlation with a structure-dynamics correlation measure obtained from isoconfigurational ensemble simulations. Interestingly, the two systems showing the highest structure-dynamics correlation, LJ at rho = 1.1 and the (8, 5) model, are respectively the least and most fragile within their classes. These systems exhibit broad mobility distributions and large non-Gaussian parameters but low four-point susceptibilities, suggesting a decoupling between the spatial correlation length and mobility contrast. Both systems lie in the enthalpy-dominated regime and are close to the spinodal, pointing to mechanical instability as a source of heterogeneity. Our results reveal that the structure-dynamics correlation is more closely linked to the contrast in individual particle mobility than to the spatial extent of dynamic correlations that typically scale with fragility.

10adynamical heterogeneities10aGlasses10aglassy dynamics10aslow relaxation10astructural1 aSharma, Mohit1 aSastry, Srikanth1 aBhattacharyya, Sarika, Maitra uhttps://library.ncl.res.in/content/structure-dynamics-correlation-and-its-link-fragility-and-dynamic-heterogeneity