Vanadium sesquioxide (V2O3) exhibits a metal–insulator transition (MIT) at 160 K between a low temperature, monoclinic, antiferromagnetic Mott insulator and a high temperature, rhombohedral, paramagnetic, metallic phase. In thin films, a percolative transition takes place over a finite temperature range of phase coexistence. We study the fluctuating dynamics of this percolative MIT by measuring voltage noise spectra at both low frequencies (up to 100 kHz) and radio frequencies (between 10 MHz and 1 GHz). Noise intensity quadratic in bias is observed in the MIT region, as expected for resistive fluctuations probed nonperturbatively by the current. The low frequency noise resembles flicker-type 1/fβ noise, often taking on the form of Lorentzian noise dominated by a small number of fluctuators as the volume fraction of the insulating phase dominates. Radio frequency noise intensity also quadratic in the bias current allows the identification of resistance fluctuations with lifetimes below 1 ns, approaching timescales seen in non-equilibrium pump–probe studies of the transition. We find quantitative consistency with a model for fluctuations in the percolative fraction. The thermodynamics of the MIT suggests that dominant fluctuations are ones that alter small volumes affecting the connectivity of domain boundaries. This noise serves as a sensitive and nonperturbative probe for the dynamics of switching phenomena in this system.

中文翻译：

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金属-绝缘体转变中 V2O3 薄膜中的渗流和纳秒波动器

倍半氧化钒 (V2O3) 在 160 K 时在低温、单斜、反铁磁莫特绝缘体和高温、菱面体、顺磁性金属相之间表现出金属-绝缘体转变 (MIT)。在薄膜中，在有限的相共存温度范围内发生渗透转变。我们通过测量低频（高达 100 kHz）和无线电频率（10 MHz 和 1 GHz 之间）的电压噪声谱来研究这种渗透性 MIT 的波动动态。在 MIT 区域观察到噪声强度二次方偏差，正如预期的电流无扰动探测的电阻波动。低频噪声类似于闪烁型 1/fβ 噪声，通常采用洛伦兹噪声的形式，由少数波动子主导，因为绝缘相的体积分数占主导地位。偏置电流中的射频噪声强度也是二次方的，可以识别寿命低于 1 ns 的电阻波动，接近过渡的非平衡泵 - 探针研究中看到的时间尺度。我们发现与渗透分数波动模型的定量一致性。麻省理工学院的热力学表明，主要波动是改变影响域边界连通性的小体积的波动。这种噪声可用作该系统中开关现象动态的灵敏且无扰动的探针。我们发现与渗透分数波动模型的定量一致性。麻省理工学院的热力学表明，主要波动是改变影响域边界连通性的小体积的波动。这种噪声可用作该系统中开关现象动态的灵敏且无扰动的探针。我们发现与渗透分数波动模型的定量一致性。麻省理工学院的热力学表明，主要波动是改变影响域边界连通性的小体积的波动。这种噪声可用作该系统中开关现象动态的灵敏且无扰动的探针。