Since the memristor was theoretically predicted at 1971, the research on memristor and memristive behavior has attracted great interest. However, there is a debate about the physical model of the non–zero-crossing (or named non-pinched) current-voltage (I–V) hysteresis behavior observed experimentally in many reported memristive devices. By identifying and analyzing all these non–zero-crossing hysteresis curves, we attribute this behavior to three mechanisms: the involvement of a capacitive effect, the appearance of a ferroelectric or piezoelectric polarization, and the formation of an internal electromotive force. Among them, the memristive behavior involving a capacitive effect has been reported extensively. It demonstrates that the combination of multiple physical properties (memristive and capacitive) in a single device could prefigure potential multifunctional applications. In this review, we discuss the physical mechanism of non–zero-crossing I–V curves, the related research progress with particular emphasis on the origin of non–zero-crossing I–V curves. Moreover, the existing problems in this field and the possible solutions will be discussed, providing an outlook for the future developments.

自从1971年从理论上预测忆阻器以来，忆阻器和忆阻行为的研究引起了极大的兴趣。但是，关于在许多报道的忆阻器件中通过实验观察到的非零交叉（或称为非捏合）电流-电压（IV）磁滞行为的物理模型存在争议。通过识别和分析所有这些非零交叉的磁滞曲线，我们将这种行为归因于三种机理：电容效应的参与，铁电或压电极化的出现以及内部电动势的形成。其中，涉及电容效应的忆阻行为已被广泛报道。它证明了在单个设备中多种物理特性（忆阻和电容）的组合可以预示潜在的多功能应用。在这篇综述中，我们讨论了非零交叉IV曲线的物理机理，以及相关的研究进展，特别着重于非零交叉IV曲线的起源。此外，将讨论该领域中存在的问题和可能的解决方案，为未来的发展提供前景。