In this paper, we proposed a bi-tunable terahertz (THz) metamaterial absorber based on bulk Dirac semimetal (BDS) and strontium titanate (STO). When the values of Fermi energy E_F and temperature (T) are equal to 40 meV and 300 K, the simulation result shows that the absorption frequency is centered at 3.69 THz with nearly 100% absorption rates. Interestingly, by adjusting the Fermi energy E_F of the BDS pattern from 10 to 80 meV, the peak absorptivity can be continuously tuned from 70% to 99.9%, and the absorption frequency point shifts from 3.265 to 4.82 THz. Meanwhile, when the temperature of the STO metamaterial changes from 200 to 300 K, the absorption frequency point can be dynamically controlled from 2.665 to 3.69 THz with a fixed amplitude. When Fermi energy E_F of the BDS and temperature T of STO were varied, the relative impedances of the absorber were investigated. Furthermore, the electric field and power loss density distributions were also examined to further explain the related physical mechanism. Owing to its symmetrical structure, the proposed absorber demonstrates intensity polarization-independent characteristics and can maintain stable absorption with a large range of incident angles. The proposed absorber may be used in various devices such as detectors, selective heat emitters, and smart devices.

中文翻译：

---

基于狄拉克半金属和钛酸锶的热电双调谐吸收器。

在本文中，我们提出了一种基于体狄拉克半金属（BDS）和钛酸锶（STO）的双可调太赫兹（THz）超材料吸收器。当费米能量E _F和温度（T）的值分别等于40 meV和300 K时，仿真结果表明，吸收频率以3.69 THz为中心，吸收率接近100％。有趣的是，通过调整费米能量E _F从10到80 meV的BDS模式，峰值吸收率可以从70％连续调谐到99.9％，吸收频率点从3.265 THz转变为4.82 THz。同时，当STO超材料的温度从200 K变为300 K时，可以动态地将吸收频率点控制在2.665 THz至3.69 THz之间，并具有固定的幅度。当费米BDS的能量E _F和温度T改变STO的阻抗，研究吸收器的相对阻抗。此外，还检查了电场和功率损耗密度分布，以进一步解释相关的物理机制。由于其对称的结构，所提出的吸收体表现出强度偏振无关的特性，并且可以在大入射角范围内保持稳定的吸收。所提出的吸收器可用于各种设备中，例如探测器，选择性热辐射器和智能设备。