Conductive and electrostatic atomic force microscopy (cAFM and EFM) are used to investigate the electric conduction at nominally neutral domain walls in hexagonal manganites. The EFM measurements reveal a propensity of mobile charge carriers to accumulate at the nominally neutral domain walls in ErMnO3, which is corroborated by cAFM scans showing locally enhanced d.c. conductance. Our findings are explained based on established segregation enthalpy profiles for oxygen vacancies and interstitials, providing a microscopic model for previous, seemingly disconnected observations ranging from insulating to conducting domain wall behavior. In addition, we observe variations in conductance between different nominally neutral walls that we attribute to deviations from the ideal charge-neutral structure within the bulk, leading to a superposition of extrinsic and intrinsic contributions. Our study clarifies the complex transport properties at nominally neutral domain walls in hexagonal manganites and establishes new possibilities for tuning their electronic response based on oxidation conditions, opening the door for domain-wall based sensor technology.

中文翻译：

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六方锰酸盐名义中性畴壁的内在和外在传导贡献

导电和静电原子力显微镜（cAFM 和 EFM）用于研究六方锰酸盐中标称中性畴壁的导电性。EFM 测量揭示了移动电荷载流子在 ErMnO3 中标称中性畴壁处积累的倾向，这得到了显示局部增强直流电导的 cAFM 扫描的证实。我们的研究结果是基于已建立的氧空位和间隙的分离焓分布来解释的，为以前的微观模型提供了一个微观模型，从绝缘到导电畴壁行为，看似不相关的观察结果。此外，我们观察到不同标称中性壁之间的电导变化，我们将其归因于与本体中理想电荷中性结构的偏差，导致外在和内在贡献的叠加。我们的研究阐明了六方锰酸盐中标称中性畴壁的复杂传输特性，并建立了基于氧化条件调整其电子响应的新可能性，为基于畴壁的传感器技术打开了大门。