Watson Matthew D, Louat Alex, Cacho Cephise, Choi Sungkyun, Lee Young Hee, Neumann Michael, Kim Gideok
Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon, 16419, Republic of Korea.
Nat Commun. 2023 Jun 9;14(1):3388. doi: 10.1038/s41467-023-39114-z.
Charge Density Waves (CDW) are commonly associated with the presence of near-Fermi level states which are separated from others, or "nested", by a wavector of q. Here we use Angle-Resolved Photo Emission Spectroscopy (ARPES) on the CDW material TaNiSe and identify a total absence of any plausible nesting of states at the primary CDW wavevector q. Nevertheless we observe spectral intensity on replicas of the hole-like valence bands, shifted by a wavevector of q, which appears with the CDW transition. In contrast, we find that there is a possible nesting at 2q, and associate the characters of these bands with the reported atomic modulations at 2q. Our comprehensive electronic structure perspective shows that the CDW-like transition of TaNiSe is unique, with the primary wavevector q being unrelated to any low-energy states, but suggests that the reported modulation at 2q, which would plausibly connect low-energy states, might be more important for the overall energetics of the problem.
电荷密度波（CDW）通常与近费米能级态的存在相关联，这些态与其他态通过波矢q相互分离，即“嵌套”。在此，我们对CDW材料TaNiSe进行了角分辨光电子能谱（ARPES）研究，发现在主CDW波矢q处完全不存在任何合理的态嵌套。然而，我们在类空穴价带的复制带上观察到光谱强度，其波矢偏移了q，且随着CDW转变而出现。相比之下，我们发现2q处存在可能的嵌套，并将这些能带的特征与报道的2q处的原子调制联系起来。我们全面的电子结构观点表明，TaNiSe的类CDW转变是独特的，主波矢q与任何低能态无关，但表明报道的2q处的调制可能对该问题的整体能量学更为重要，因为它可能合理地连接低能态。
