# On the Study of Advanced Nanostructured Semiconductor-Based Metamaterial
## 1 Introduction  
Metamaterials have inspired scientists to think about their fascinating properties, including allowing for the nonconventional propagation of electromagnetic waves. These include negative phase velocity or negative refraction. Nanostructured metamaterials, a class of hyperbolic composites, are making a substantial contribution to the field. A significant number of attractive applications, for example, ultracompact wave plates [1], broadband absorbers [2], and optical circuit boards [3], has been possible due to numerous unusual trends in anisotropic composites. These include invisible cloak [4], negative refraction [5], and abnormal refection [6]. It should be noted that electromagnetic features of composites can be engineered by lights [7], electrics [8], magnetics [9], temperatures [10], and engineering material structure or geometry of metamaterial unit cells.  
It should be mentioned that most of the presented reconfigurable metamaterials, composed of noble metals, lack a direct tuning option. The former occurs due to the fact that free electrons in metal unit cells are unmanageable. The findings presented up to now have focused on changing features of substrates or structures aiming to tune the metamaterial properties. These include refractive index [11], depletion width of GaAs [12], optical constants of graphene [13], permittivity of ITO [14], shape of PDMS [15], and vanadium dioxide conductivity [16]. In addition to changing the response of the materials that are used to construct metamaterials, structurally engineering meta-atoms are considered another efficient approach to reconfigure the metamaterial properties [17]. In comparison with direct metamaterial tuning, these indirect engineering techniques do not allow to go beyondthe current state of the art. Enabling the control of free electrons in metamaterial unit cells, the direct tuning technique can benefit from an adequately large free electron distribution and density variation in a material (e.g., heavily doped semiconductor or conducting oxide). The former may result in the variation in resonance frequency and resonance strength of composites. Unsurprisingly, this immediately reconfigurable metamaterial approach will benefit due to a combination of benefits of the individual modulation of metamaterial building blocks, leading to exceptionally lower power dissipation.  
However, to date, no comprehensive research has been related to direct tuning techniques applied for metamaterials composed of directly reconfigurable inclusions. The main outstanding feature of immediately tunable metamaterials is the variability in the electromagnetic property of the metamaterial building blocks. For instance, doped semiconductors, such as GaAs, InSb, InAs, and ZnO, and conducting oxides, such as ITO [14], are classic examples of materials comprising free electrons (free carriers) that are easily tunable by means of electric fields, pumping lights, or temperature fields. These instances can additionally be employed to create metamaterials [18]. In this paper, semiconductors were applied with the aim of modeling nanostructured semiconductor metamaterials to show a directly reconfigurable metamaterial approach, providing a fertile ground for dynamic electric control. Herein, metamaterial unit cells are created by employing doped semiconductors. The former would allow to deal with metal with a minor metamaterial case.