The first, developed by Hutson and White and described in Elastic Wave Propagation in Piezoelectric Semiconductors Journal of Applied Physics, 33, page 40 , provides {HEAD ~ a coupling mechanism} between {TAIL ~ phonons} and electrons and leads to absorption and dispersion of the acoustic wave by free charge carriers 
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The first , developed by Hutson and White and described in Elastic Wave Propagation in Piezoelectric Semiconductors Journal of Applied Physics , 33 , page 40 , provides { HEAD ~ a coupling mechanism } between { TAIL ~ phonons } and electrons and leads to absorption and dispersion of the acoustic wave by free charge carriers
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