(a)CuTe在低溫（77K），透過掃描穿隧顯微鏡實驗觀測到沿晶軸a軸（紅色箭頭）之CDW晶格調變。(b)沿晶軸a軸，CDW態形成超晶胞（紅色虛線）的原子高度輪廓線。(c)透過第一性原理計算，與(b)圖超晶胞（紅色虛線）週期一致之電荷分布。(d)低溫下，實驗推測CuTe結構層間耦合所致之三維層間（紅色虛線與藍色虛線方框）反相位CDW態。(e)與(d)圖一致之第一性原理計算，CDW導致的層間反相位電荷變化，灰色與紅色分別代表電荷增加與減少。（圖／薛宏中提供）

2. (a) CDW modulation in copper telluride (CuTe) along the crystallographic a-axis (red arrow) observed by scanning tunneling microscopy experiments at a low temperature (77K). (b) Atomic height profile of the CDW state forming superlattice along the crystallographic a-axis (red dashed line). (c) First-principles calculated charge density distribution in a specific superlattice periodicity, which agrees perfectly with the unit shown in (b). (d) Schematics of a three-dimensional anti-phase CDW state (red/blue dashed boxes) along the c-axis induced by interlayer coupling of CuTe structures at low temperature. (e) Modulated structure of the CDW in (d) with charge density difference between CDW and non-CDW states obtained by first-principles calculations ( gray (red) area denotes the increasing (decreasing) in corresponding charge density).