Two Parameters Synergistic Modulation

1 Synergistic Optimization of the Seebeck Coefficient and Thermai Conductivity 

In addition, quasicrystal material is also a promising thermoelectric material. Quasicrystals have special fivefold and tenfold symmetries which cannot exist in crystal and amorphous materials. A large number of small gaps near the Fermi surface exist in these compounds, which can be destroyed with the temperature variation. Then the shape of the Fermi surface will change, and finally enhance the 

Seebeck coefficient [107]. Moreover, due to the aperiodic order in the lattice, the thermal transport process behaves like a glass, which endows them with very low thermal conductivity, two orders of magnitude lower than common alloy [108, 109]. 

2 Synergistic Optimization of Electrical Conductivity and Thermal Conductivity 

The clathrate is another typical PGEC material [119-127], which is mainly composed of group IVA elements and can be expressed as AxByC46 y, where B and C atoms constitute a pentagonal dodecahedron fullerene cage framework and a lot of clathrate voids can accommodate foreign atom A (as shown in Fig. 1.9b). In these voids, due to the weak chemical bonds with the surrounding atoms, the 

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