Chen Huandong, Zhao Boyang, Mutch Josh, Jung Gwan Yeong, Ren Guodong, Shabani Sara, Seewald Eric, Niu Shanyuan, Wu Jiangbin, Wang Nan, Surendran Mythili, Singh Shantanu, Luo Jiang, Ohtomo Sanae, Goh Gemma, Chakoumakos Bryan C, Teat Simon J, Melot Brent, Wang Han, Pasupathy Abhay N, Mishra Rohan, Chu Jiun-Haw, Ravichandran Jayakanth
Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA.
Department of Physics, University of Washington, Seattle, WA, 98195, USA.
Adv Mater. 2023 Dec;35(49):e2303283. doi: 10.1002/adma.202303283. Epub 2023 Oct 27.
As one of the most fundamental physical phenomena, charge density wave (CDW) order predominantly occurs in metallic systems such as quasi-1D metals, doped cuprates, and transition metal dichalcogenides, where it is well understood in terms of Fermi surface nesting and electron-phonon coupling mechanisms. On the other hand, CDW phenomena in semiconducting systems, particularly at the low carrier concentration limit, are less common and feature intricate characteristics, which often necessitate the exploration of novel mechanisms, such as electron-hole coupling or Mott physics, to explain. In this study, an approach combining electrical transport, synchrotron X-ray diffraction, and density-functional theory calculations is used to investigate CDW order and a series of hysteretic phase transitions in a dilute d-band semiconductor, BaTiS . These experimental and theoretical findings suggest that the observed CDW order and phase transitions in BaTiS may be attributed to both electron-phonon coupling and non-negligible electron-electron interactions in the system. This work highlights BaTiS as a unique platform to explore CDW physics and novel electronic phases in the dilute filling limit and opens new opportunities for developing novel electronic devices.
作为最基本的物理现象之一，电荷密度波（CDW）序主要出现在准一维金属、掺杂铜酸盐和过渡金属二硫属化物等金属体系中，在这些体系中，基于费米面嵌套和电子 - 声子耦合机制，人们对其有很好的理解。另一方面，半导体体系中的CDW现象，特别是在低载流子浓度极限下，较为少见且具有复杂的特征，这通常需要探索诸如电子 - 空穴耦合或莫特物理等新机制来解释。在本研究中，采用电输运、同步辐射X射线衍射和密度泛函理论计算相结合的方法，研究了稀d带半导体BaTiS中的CDW序和一系列滞后相变。这些实验和理论结果表明，在BaTiS中观察到的CDW序和相变可能归因于体系中的电子 - 声子耦合以及不可忽略的电子 - 电子相互作用。这项工作突出了BaTiS作为一个独特的平台，可用于在稀填充极限下探索CDW物理和新型电子相，并为开发新型电子器件开辟了新机会。
