TY - JOUR

T1 - Electric-dipole transitions between group-III acceptor states in uniaxially compressed Ge

AU - Wang, Ta-Hui

AU - Yen, Shun-Tung

PY - 2010/8/10

Y1 - 2010/8/10

N2 - We study the electric-dipole transitions between group-III acceptor states in Ge under stress along the [001] crystallographic direction in the effective mass approximation. We systematically investigate the cases of zero stress, infinitesimal stress, and finite stress including the low-stress and the high-stress regions. Our results show quantitative agreement with experimental data at zero stress and at infinitesimal stress. The relative intensities of infinitesimal-stress-induced components of transitions from the 1τg+ state to the nτ8- states do not correlate significantly with the species of acceptors except for the transition to the 1τ8-state. The oscillator strengths of some transitions are susceptible to the stress in the low-stress region (<0.3 kbar), and could be zero at a specific stress. The behaviours of the stress dependence of oscillator strengths for different transition lines are explained in terms of the compositions of the wavefunctions and the dipole matrix elements. In the high-stress region (≳3 kbar), the ground state is s-like, and only the transitions to the p-like states can have non-negligible oscillator strengths. The photon absorbed (emitted) and associated with each electric-dipole transition between the s-like and the p-like states is polarized either parallel or perpendicular to the stress direction. We also calculate the absorption spectra for Ge:Ga at liquid-helium temperature. The results are in good agreement with experiment.

AB - We study the electric-dipole transitions between group-III acceptor states in Ge under stress along the [001] crystallographic direction in the effective mass approximation. We systematically investigate the cases of zero stress, infinitesimal stress, and finite stress including the low-stress and the high-stress regions. Our results show quantitative agreement with experimental data at zero stress and at infinitesimal stress. The relative intensities of infinitesimal-stress-induced components of transitions from the 1τg+ state to the nτ8- states do not correlate significantly with the species of acceptors except for the transition to the 1τ8-state. The oscillator strengths of some transitions are susceptible to the stress in the low-stress region (<0.3 kbar), and could be zero at a specific stress. The behaviours of the stress dependence of oscillator strengths for different transition lines are explained in terms of the compositions of the wavefunctions and the dipole matrix elements. In the high-stress region (≳3 kbar), the ground state is s-like, and only the transitions to the p-like states can have non-negligible oscillator strengths. The photon absorbed (emitted) and associated with each electric-dipole transition between the s-like and the p-like states is polarized either parallel or perpendicular to the stress direction. We also calculate the absorption spectra for Ge:Ga at liquid-helium temperature. The results are in good agreement with experiment.

UR - http://www.scopus.com/inward/record.url?scp=77957062904&partnerID=8YFLogxK

U2 - 10.1088/0953-8984/22/34/345801

DO - 10.1088/0953-8984/22/34/345801

M3 - Article

C2 - 21403263

AN - SCOPUS:77957062904

SN - 0953-8984

VL - 22

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

IS - 34

M1 - 345801

ER -