Details

Autor(en) / Beteiligte

• Kim, R H J
• Pathak, A K
• Park, J-M
• Imran, M
• Haeuser, S J
• Fei, Z
• Mudryk, Y
• Koschny, T
• Wang, J

Titel

Nano-compositional imaging of the lanthanum silicide system at THz wavelengths

Ist Teil von

• Optics express, 2024-01, Vol.32 (2), p.2356-2363

Ort / Verlag

United States: Optical Society of America

Erscheinungsjahr

2024

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Terahertz scattering-type scanning near-field optical microscopy (THz-sSNOM) provides a noninvasive way to probe the low frequency conductivity of materials and to characterize material compositions at the nanoscale. However, the potential capability of atomic compositional analysis with THz nanoscopy remains largely unexplored. Here, we perform THz near-field imaging and spectroscopy on a model rare-earth alloy of lanthanum silicide (La-Si) which is known to exhibit diverse compositional and structural phases. We identify subwavelength spatial variations in conductivity that is manifested as alloy microstructures down to much less than 1 μm in size and is remarkably distinct from the surface topography of the material. Signal contrasts from the near-field scattering responses enable mapping the local silicon/lanthanum content differences. These observations demonstrate that THz-sSNOM offers a new avenue to investigate the compositional heterogeneity of material phases and their related nanoscale electrical as well as optical properties.