Infrared nanoimaging of the metal-insulator transition in the charge-density-wave van der Waals material 1 T − TaS 2
Infrared nanoimaging of the metal-insulator transition in the charge-density-wave van der Waals material 1 T − TaS 2
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DOI：
10.1103/physrevb.97.035111
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发表时间：
2018-01
影响因子：
3.7
通讯作者：
A. Frenzel;A. Mcleod;Dennis Wang;Yu Liu;Wenjian Lu;G. Ni;A. W. Tsen;Yuping Sun;A. Pasupathy;D. Basov
中科院分区：
文献类型：
--
作者：
A. Frenzel;A. Mcleod;Dennis Wang;Yu Liu;Wenjian Lu;G. Ni;A. W. Tsen;Yuping Sun;A. Pasupathy;D. Basov
利用低温扫描近场光学显微镜，研究了衬底上剥离微晶的一级金属-绝缘体转变。我们清楚地观察到空间分离的金属和绝缘状态之间的过渡期间的相称和近相称的电荷密度波阶段。在纳米长度尺度上探测电动力学的能力揭示了在转变温度附近绝缘和金属区域的温度依赖性电子性质。在固定的温度下，观察到绝缘和金属区域之间的一个非常宽的空间边界，跨越该边界的纳米光信号在几百纳米的长度尺度上平稳地演化。为了理解这些观测结果，我们进行了金斯堡-朗道计算，以确定畴界的电荷密度波结构，这揭示了存在一个中间电子相，该电子相具有不同于本体热力学相的独特性质。
Using scanning near-field optical microscopy at cryogenic temperatures, we explored the first-order metal-insulator transition of exfoliatedmicrocrystals on asubstrate. We clearly observed spatially separated metallic and insulating states during the transition between commensurate and nearly commensurate charge-density-wave phases. The capability to probe electrodynamics on nanometer length scales revealed temperature-dependent electronic properties of the insulating and metallic regions near the transition temperature. At fixed temperature, a remarkably broad spatial boundary between insulating and metallic regions was observed, across which the nano-optical signal smoothly evolved over a length scale of several hundred nanometers. To understand these observations, we performed Ginzburg-Landau calculations to determine the charge-density-wave structure of the domain boundary, which revealed the existence of an intermediate electronic phase with unique properties distinct from the bulk thermodynamic phases.