A metallic mosaic phase and the origin of Mott-insulating state in 1T-TaS2.
A metallic mosaic phase and the origin of Mott-insulating state in 1T-TaS2.
复制标题
DOI：
10.1038/ncomms10956
复制
发表时间：
2016-03-10
影响因子：
16.6
通讯作者：
Zhang Y
中科院分区：
文献类型：
--
作者：
Ma L;Ye C;Yu Y;Lu XF;Niu X;Kim S;Feng D;Tománek D;Son YW;Chen XH;Zhang Y
电子-电子和电子-声子相互作用是稳定物质各种电荷有序相的两种主要驱动力。在层状化合物1T-TaS2中，两者之间复杂的相互作用产生了具有特殊电荷密度波（CDW）顺序的莫特绝缘基态。这种微妙的平衡也使得利用外部扰动在这种材料中创造和操纵新的相成为可能。在这里，我们研究了电压脉冲诱导的镶嵌CDW相，发现新相具有与原始Mott基态完全不同的电子结构。镶嵌相由纳米尺寸的畴组成，其特征是最顶层CDW顺序参数的相移，以及相对于下面各层的堆叠改变。我们发现新相的性质是由堆叠顺序决定的，我们的结果为1T-TaS2中Mott相的起源提供了新的线索。在相关材料中，当多体相互作用之间的平衡被打乱时，就会出现新的相。在这里，Ma等人通过电压脉冲在层状1T-TaS2中诱导出Mott绝缘态的镶嵌电荷密度波相，揭示了层间堆叠顺序的主导作用。
Electron–electron and electron–phonon interactions are two major driving forces that stabilize various charge-ordered phases of matter. In layered compound 1T-TaS2, the intricate interplay between the two generates a Mott-insulating ground state with a peculiar charge-density-wave (CDW) order. The delicate balance also makes it possible to use external perturbations to create and manipulate novel phases in this material. Here, we study a mosaic CDW phase induced by voltage pulses, and find that the new phase exhibits electronic structures entirely different from that of the original Mott ground state. The mosaic phase consists of nanometre-sized domains characterized by well-defined phase shifts of the CDW order parameter in the topmost layer, and by altered stacking relative to the layers underneath. We discover that the nature of the new phase is dictated by the stacking order, and our results shed fresh light on the origin of the Mott phase in 1T-TaS2. In correlated materials, new phases emerge when the balance between many-body interactions is perturbed. Here, Ma et al. induce a mosaic charge-density-wave phase out of Mott insulating state in layered 1T-TaS2 by voltage pulses, which reveals a dominating role of interlayer stacking order.