In-Plane Anisotropy in van der Waals NiTeSe Ternary Alloy

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Anisotropic material properties are crucial for diverse electronic, magnetic, optical, and mechanical applications.
• Ni-based van der Waals materials, such as NiTe2, are of interest due to their unique characteristics.

Purpose of the Study:

• To investigate the anisotropic properties of NiTe2 and the NiTeSe alloy.
• To understand how selenium substitution influences the in-plane anisotropy of NiTe2.

Main Methods:

• Utilized scanning tunneling microscopy (STM) for real-space imaging.
• Employed angle-resolved photoemission spectroscopy (ARPES) for electronic structure analysis.
• Performed density functional theory (DFT) calculations for theoretical validation.

Main Results:

• NiTeSe exhibits pronounced in-plane anisotropy, unlike the trigonal symmetry of 1T-NiTe2.
• STM revealed linear charge distribution order in NiTeSe.
• ARPES and DFT showed an anisotropic Fermi surface elongated along the ky direction.
• Fermi velocity varied directionally, being highest along kx and lowest along ky.

Conclusions:

• Selenium substitution effectively induces and tunes in-plane anisotropy in Ni-based van der Waals materials.
• The observed anisotropy offers potential for developing novel anisotropic electronic and optoelectronic devices.
• Findings highlight the tunability of properties in ternary transition metal dichalcogenide systems.