{'fraction_non_alphanumeric': 0.030379746835443037, 'fraction_numerical': 0.02362869198312236, 'mean_word_length': 4.842364532019705, '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}}
The importance of singly charged oxygen vacancies for electrical conduction in monoclinic HfO2

The point-defect structure of monoclinic HfO 2 (m-HfO 2) was studied by means of equilibrium electrical conductance measurements as a function of temperature 1050 ≤ T / K ≤ 1200 and oxygen partial pressure − 20 ≤ log ( p O 2 / bar ) ≤ − 2. The total conductivity σ displayed similar behavior at each temperature examined. In oxidizing conditions ( p O 2 ≥ 10 − 7 bar), the total conductivity increased with increasing oxygen partial pressure and was assigned to hole conduction. Around 10 − 10 bar, a region of almost constant conductivity was found; this is ascribed to ionic conduction by means of doubly charged oxygen vacancies. In reducing conditions ( p O 2 ≤ 10 − 16 bar), the total conductivity surprisingly decreased with decreasing oxygen partial pressure. Defect-chemical modeling indicates that this behavior is consistent with the conversion of mobile doubly charged oxygen vacancies into less mobile singly charged vacancies by electron trapping. Point-defect concentrations at the oxygen partial pressures relevant to resistive switching devices are predicted and discussed.