2001/01/05 by William Garber, W. Garber, Folkert M. Tangerman +8
Engineering · Materials Science · Physics and Astronomy · #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Material Dynamics and Properties #Materials Science (cond-mat.mtrl-sci) #Theoretical and Computational Physics #Thin-Film Transistor Technologies #cond-mat.dis-nn #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0101070
4 pages with 2 embedded postscript figures
arxiv created 2001/01/05 · openalex publication_date 2001/01/05 · arxiv updated 2009/11/30 · openalex created_date 2022/10/05 · openalex updated_date 2026/07/28
Numerical studies of amorphous silicon in harmonic approximation show that\nthe highest 3.5% of vibrational normal modes are localized. As vibrational\nfrequency increases through the boundary separating localized from delocalized\nmodes, near omegac=70meV, (the "mobility edge") there is a\nlocalization-delocalization (LD) transition, similar to a second-order\nthermodynamic phase transition. By a numerical study on a system with 4096\natoms, we are able to see exponential decay lengths of exact vibrational\neigenstates, and test whether or not these diverge at omegac. Results are\nconsistent with a localization length xi which diverges above omegac as\n(omega-omegac)-p where the exponent is p = 1.3 +/- 0.5. Below the mobility\nedge we find no evidence for a diverging correlation length. Such an asymmetry\nwould contradict scaling ideas, and we suppose it is a finite-size artifact. If\nthe scaling regime is narrower than our 1 meV resolution, then it cannot be\nseen directly on our finite system.\n