Institute of Industrial Science, University of Tokyo
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Institute of Industrial Science, University of Tokyo Hajime Tanaka , Hiroshi Shintani, Takeshi Kawasaki, and Keiji Watanab e Hidden order in supercooled liquid s Dynamic heterogeneity is considered to be a clue to the mechanism of the liquid-glass transition, but the physical origin of dynamic heterogeneity has not been clarified. Recent numerical studies and experiments demonstrated the existence of m edium-range crystalline order (MRCO) in supercooled liquids, and suggested that MRCO may be the origin of dynamic heterog eneity. Dynamic Heterogeneity and Medium-range Crystalline Order (MRCO) H. Shintani and H. Tanaka, Nat. Phys. 2, 200 (2006). Driven Granular Matter as a Model System (2DGL) by T. Kawasaki et al. Diverging correlation length and slow dynamics Relationship between MRCO and Dynamic Heterogeneity k jk j j i n 6 exp 1 6 ) 0 ( ) ( ) ( 6 6 6 r r g r r r g r g exp ) ( ) ( 2 1 6 Fitting by 2D Ornstein-Zernike function: ガガガガ 1.0 0.6 0.4 0.2 0.0 0.8 dt t t j j 6 6 1 Distribution of Trajecto ry 2D polydiperse colloidal system (2DPC) 2D spin liquid (2DSL) 0 2 4 6 8 10 0 0.1 0.2 0.3 0.4 0.5 r/< d > g 6 ( r)/ g ( r) 77.4% 70.0% 62.6% 2DSL 2DPC 2DGL 3DPC Absence of static spatial density correlation The Message of our work Contrary to the common belief, we demonstrate that there is ‘static’ heterogeneity in an in stantaneous structure of a supercooled liquid, if we look it through the proper order parame ter, and it is the origin of ‘dynamic heterogeneity’. However, since medium-range crystalli ne order (MRCO) does not accompany the density change, MRCO cannot be detected by the static two-body density correlator. We propose that slow dynamics is caused by the critical-like di vergence of MRCO toward the ideal glass transition point. This scenario suggests an intrigu ing link between glass-transition and critical phenomena. T. Kawasaki, T. Araki & H. Tanaka, PRL 99, 215701 (2007). K.Watanabe & H. Tanaka, PRL 100,158002 (200 8). There is no indication of static de nsity correlation in S(q) in the region o f q ～ 1/ξ. Instead, there are shoulders in the main peak and splitting of the second peak. The fact that MRCO does not accompa ny any density change means that MR CO cannot be detected by the two-po int density correlator. 2DSL 2DPC
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Hidden order in supercooled liquids. Diverging correlation length and slow dynamics. Numerical and experimental evidence for static signature of dynamic heterogeneity in supercooled liquids. Institute of Industrial Science, University of Tokyo - PowerPoint PPT Presentation
Transcript of Institute of Industrial Science, University of Tokyo
Institute of Industrial Science, University of Tokyo Hajime Tanaka, Hiroshi Shintani, Takeshi Kawasaki, and Keiji Watanabe
Hidden order in supercooled liquids
Dynamic heterogeneity is considered to be a clue to the mechanism of the liquid-glass transition, but the physical origin of dynamic heterogeneity has not been clarified. Recent numerical studies and experiments demonstrated the existence of medium-range crystalline order (MRCO) in supercooled liquids, and suggested that MRCO may be the origin of dynamic heterogeneity.
Dynamic Heterogeneity and Medium-range Crystalline Order (MRCO)
H. Shintani and H. Tanaka, Nat. Phys. 2, 200 (2006).
Driven Granular Matter as a Model System (2DGL)
by T. Kawasaki et al.
Diverging correlation length and slow dynamics
Relationship between MRCO and Dynamic Heterogeneity
k
jkj
j in
6exp1
6
)0()()( 666 rrg
rrrgrg exp)()( 2
1
6
Fitting by 2D Ornstein-Zernike function:
ガラス板1.0
0.6
0.4
0.2
0.0
0.8
dtt
t
jj
661
Distribution of Trajectory
2D polydiperse colloidal system (2DPC)
2D spin liquid (2DSL)
0 2 4 6 8 100
0.1
0.2
0.3
0.4
0.5
r/<d>
g 6(r
)/g(r)
77.4% 70.0% 62.6%
2DSL
2DPC 2DGL
3DPC
Absence of static spatial density correlation
The Message of our workContrary to the common belief, we demonstrate that there is ‘static’ heterogeneity in an instantaneous structure of a supercooled liquid, if we look it through the proper order parameter, and it is the origin of ‘dynamic heterogeneity’. However, since medium-range crystalline order (MRCO) does not accompany the density change, MRCO cannot be detected by the static two-body density correlator. We propose that slow dynamics is caused by the critical-like divergence of MRCO toward the ideal glass transition point. This scenario suggests an intriguing link between glass-transition and critical phenomena.
T. Kawasaki, T. Araki & H. Tanaka, PRL 99, 215701 (2007).
K.Watanabe & H. Tanaka, PRL 100,158002 (2008).
There is no indication of static density correlation in S(q) in the region of q ～ 1/ξ. Instead, there are shoulders in the main peak and splitting of the second peak.The fact that MRCO does not accompany any density change means that MRCO cannot be detected by the two-point density correlator.
2DSL 2DPC
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