The differential conductance of graphene is shown to exhibit a zero-bias anomaly at low temperatures, arising from a suppression of the quantum corrections due to weak localization and electron interactions. A simple rescaling of these data, free of any adjustable parameters, shows that this anomaly exhibits a universal, temperature- (T) independent form. According to this, the differential conductance is approximately constant at small voltages (V < k_BT/e), while at larger voltages it increases logarithmically with the applied bias. For theoretical insight into the origins of this behaviour, which is inconsistent with electron heating, we formulate a model for weak-localization in the presence of nonequilibrium transport. According to this model, the applied voltage causes unavoidable dispersion decoherence, which arises as diffusing electron partial waves, with a spread of energies defined by the value of the applied voltage, gradually decohere with one another as they diffuse through the system. The decoherence yields a universal scaling of the conductance as a function of eV/k_BT, with a logarithmic variation for eV/k_BT > 1, variations in accordance with the results of experiment. Our theoretical description of nonequilibrium transport in the presence of this source of decoherence exhibits strong similarities with the results of experiment, including the aforementioned rescaling of the conductance and its logarithmic variation as a function of the applied voltage.

石墨烯的微分电导在低温下表现出零偏置异常，这是由于弱局域化和电子相互作用对量子校正的抑制造成的。对这些数据进行简单的重新调整，无需任何可调整的参数，表明这种异常表现出一种普遍的、与温度 ( T ) 无关的形式。据此，微分电导在小电压 ( V < k _B T / e ) 下近似恒定，而在较大电压下，微分电导随施加的偏压呈对数增加。为了从理论上深入了解这种与电子加热不一致的行为的起源，我们制定了一个存在非平衡输运情况下的弱局域化模型。根据这一模型，施加的电压会导致不可避免的色散退相干，这种现象是随着电子分波的扩散而出现的，其能量的扩散由施加电压的值定义，当它们在系统中扩散时，逐渐相互退相干。退相干产生电导作为e V / k _B T函数的通用标度，对于e V / k _B T > 1 具有对数变化，变化与实验结果一致。我们对存在这种退相干源的情况下的非平衡输运的理论描述与实验结果表现出很强的相似性，包括前面提到的电导的重新缩放及其作为施加电压的函数的对数变化。