Comparative study of electronic, thermoelectric, and transport properties in germanene and carbon nanotubes

This study investigates the electronic, thermoelectric, and transport properties of Germanene nanotubes (GeNTs) using a tight-binding calculations and explores their potential advantages over carbon nanotubes (CNTs) in thermoelectric applications. The effect of external electric and magnetic fields, nanotube radius, and temperature on heat capacity, electrical conductivity, power factor, and Seebeck coefficient are systematically investigated. The heat capacity C(T) of GeNTs shows a more pronounced increase with the application of external fields, especially electric field and exceeds that of CNTs. GeNTs also exhibit a lower threshold temperature for non-zero electrical conductivity attributed to their smaller energy gap, which results from easier thermal excitation of charge carriers. This property becomes more pronounced as the electrical conductivity of GeNTs increases more rapidly with temperature than that of CNTs, particularly under stronger external fields. Additionally, the thermoelectric properties of GeNTs can be further enhanced under external fields. While CNTs possess higher Seebeck coefficients and Lorenz numbers, GeNTs demonstrate distinct advantages in tunable heat capacity and conductivity, making them promising candidates for efficient thermoelectric and nanoelectronic devices. These results underscore the potential of GeNTs as an effective alternative to CNTs for advanced energy conversion applications, demonstrating their promise as high-performance thermoelectric materials for energy conversion applications.