Researchers have developed a nonrelativistic and nonmagnetic approach to generate Terahertz (THz) waves, which can be used to probe the magnetic properties of new materials. Researchers use the anisotropic electrical conductivity of particular materials to directly exploit laser-excited, high-density charge currents across nanoscale metallic surfaces to harness the power of these currents to generate THz waves. It avoids the requirement to convert charge currents to spin-polarized currents by using the anisotropic electrical conductivity of specific materials.
The researchers employed Anisotropic, conductive heterostructures to produce broadband THz radiation from laser-excited charge currents efficiently. They generated effective THz waves without needing external fields by deflecting superdiffusive charge currents with antiferromagnetic ruthenium oxide and nonmagnetic iridium oxide.
Researchers discovered platinum (Pt) as the best metal for fabricating thin films producing THz radiation. By constructing Pt/RuO2(101) and Pt/IrO2(101) thin-film heterostructures, they produced stronger signals than commercial THz sources. The nonrelativistic, nonmagnetic approach eliminates spin-polarization by using the intrinsic features of conductive materials. It provides a high THz conversion efficiency that is par with the inverse spin-Hall effect (ISHE).
The researchers found that the key to improving conversion efficiency was to select easily obtainable conductive materials with highly anisotropic electrical conductivity. The novel nonrelativistic nonmagnetic method may offer greater scalability and flexibility than current methods, which have difficulty raising the spin-Hall angle of heavy-metal materials. High-density charge currents over metallic surfaces may be efficiently harnessed to generate THz waves, which might be used to develop artificial photosynthesis, solar cell technology, and high-efficiency optoelectronic devices.
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