{'fraction_non_alphanumeric': 0.017937219730941704, 'fraction_numerical': 0.0029895366218236174, 'mean_word_length': 5.568627450980392, '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}}
Double-tip piezoresponse force microscopy for quantitative measurement of the piezoelectric coefficient at the nanoscale

Since the rotational symmetry of an electric field induced by piezoresponse force microscopy (PFM) can be broken and tuned by a scanning probe microscope (SPM) using multiple tips, a double-tip PFM measurement method is proposed to quantitatively determine the piezoelectric coefficient d33 at the nanoscale, realized by modulating the spacing or voltage ratio between two SPM tips. Compared to the traditional PFM using a single SPM tip, the piezoelectric coefficient measured by the double-tip method agrees much better with the intrinsic value.