{'fraction_non_alphanumeric': 0.034227567067530065, 'fraction_numerical': 0.004625346901017576, 'mean_word_length': 5.402366863905326, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Behaviour of diffusion thermopower in Bloch–Grüneisen regime in AlGaAs/GaAs and AlGaN/GaN heterostructures

The behaviour of diffusion thermopower Sd, in AlGaAs/GaAs and AlGaN/GaN heterojunctions, in the Bloch‐Grüneisen (BG) regime is examined taking into account the temperature dependent effects arising from screening of the electron‐phonon interaction and thermal averaging over the carrier distribution. Sd is found to follow a non‐linear temperature dependence before becoming linear as it approaches T = 0 K. This is in contrast to the usual linear dependence used, in literature, in the analysis of thermopower S. The overall behaviour of S is influenced by the phonon‐drag contribution, Sg. The calculations of both Sd and Sg, presented, demonstrate the importance of the proper inclusion of the temperature dependent effects, as in the mobility studies, in the BG regime. An analysis of the thermopower data in ultra‐pure samples at very‐low temperatures will enable better understanding of electron–phonon interaction. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)