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Title: Dynamics of hydrogen in silicon

The frequency of local hydrogen vibration in silicon and its decay process have been studied theoretically. It is believed that the H in Si is located at the bond center in equilibrium. By analyzing the discrepancy between the frequency of the antisymmetric stretching mode in a frozen-phonon calculation and the frequency in a molecular dynamic simulation, it is found that the Si–H–Si bond is dynamically bending. The reason is that the adiabatic potential along a direction perpendicular to the bond axis is so flat that random thermal motion of atoms easily scatters the H atom from the axis. A fast relaxation (∼1 ps) around the axis hides this bending from observation by slow-response measurements. One consequence of the bending is that it renders the frequency of the symmetric stretching mode higher than when the bond is not bent. Another, more interesting consequence of this bending is the fast decay rate of the antisymmetric stretching mode, in spite of its local-mode character. Again, the ease of conversion of the H motion from parallel to perpendicular to the bond axis is the cause of this fast decay, which is otherwise difficult to explain by a simple combination law of frequencies.
Authors:
 [1] ;  [2] ;  [3]
  1. ISIR, Osaka University, 8-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)
  2. International Center for Materials Nanoarchitectonics, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
  3. Grad. School of Eng. Sci., Osaka University, 1-3, Machikaneyama, Toyonaka 560-8531 (Japan)
Publication Date:
OSTI Identifier:
22263723
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1583; Journal Issue: 1; Conference: ICDS-2013: 27. international conference on defects in semiconductors, Bologna (Italy), 21-26 Jul 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BENDING; CONVERSION; DECAY; HYDROGEN; PHONONS; RELAXATION; SILICON; SIMULATION