The transition of a Mott insulator to metal, the Mott transition, can occur via carrier doping by elemental substitution¹, and by photoirradiation, as observed in transition-metal compounds^2,3,4 and in organic materials⁵. Here, we show that the application of a strong electric field can induce a Mott transition by a new pathway, namely through impulsive dielectric breakdown. Irradiation of a terahertz electric-field pulse on an ET-based compound, κ-(ET) ₂Cu[N(CN) ₂]Br (ET:bis(ethylenedithio)tetrathiafulvalene)⁶, collapses the original Mott gap of ∼30 meV with a ∼0.1 ps time constant after doublon–holon pair productions by quantum tunnelling processes, as indicated by the nonlinear increase of Drude-like low-energy spectral weights. Additionally, we demonstrate metallization using this method is faster than that by a femtosecond laser-pulse irradiation and that the transition dynamics are more electronic and coherent. Thus, strong terahertz-pulse irradiation is an effective approach to achieve a purely electronic Mott transition, enhancing the understanding of its quantum nature.

如在过渡金属化合物^2、3、4和有机材料^5中所观察到的那样，Mott绝缘体向金属的过渡，即Mott过渡，可通过元素取代^1引起的载流子掺杂和光辐照而发生。在这里，我们表明强电场的施加可以通过新途径，即通过脉冲介电击穿，诱发莫特跃迁。在基于ET的化合物κ-（ET）₂ Cu [N（CN）₂ ] Br（ET：双（亚乙基二硫代）四硫富瓦烯）⁶上辐射太赫兹电场脉冲，会使约30 meV的原始Mott间隙塌陷用〜通过量子隧穿过程产生的杜布隆-霍隆对后，时间常数为0.1 ps，这表现为类似Drude的低能谱权重的非线性增加。此外，我们证明了使用这种方法的金属化速度比飞秒激光脉冲辐照的金属化速度更快，并且过渡动力学更加电子化且具有连贯性。因此，强太赫兹脉冲辐照是实现纯电子莫特跃迁的一种有效方法，可增强对其量子性质的理解。