Effective Hamiltonian for silicene under arbitrary strain from multi-orbital basis.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Silicene, a 2D silicon allotrope, exhibits unique electronic properties influenced by strain.
• Spin-orbit interactions (SOI) are crucial for spintronic phenomena but are complex in low-dimensional materials.
• Understanding strain effects on silicene's electronic structure is key for novel device applications.

Purpose of the Study:

• To develop a comprehensive tight-binding (TB) Hamiltonian for strained silicene.
• To investigate the impact of lattice distortion and spin-orbit interactions on silicene's electronic properties.
• To explore the potential for current-induced spin accumulation and spin torque switching in strained silicene.

Main Methods:

• Derivation of a multi-orbital tight-binding Hamiltonian using Slater-Koster coupling parameters.
• Inclusion of arbitrary lattice distortions and first/second-order spin-orbit interactions (SOI).
• Application of a linearized low-energy TB Hamiltonian to model spin accumulation.

Main Results:

• The derived Hamiltonian accounts for symmetry breaking and previously neglected SOI terms.
• Strain-induced asymmetry and additional SOI terms lead to an out-of-plane spin accumulation.
• The calculated spin accumulation is unbalanced across Fermi surfaces and valleys.

Conclusions:

• The developed TB model accurately describes strained silicene's electronic and spin properties.
• The induced spin accumulation offers a viable mechanism for spin torque switching.
• This work paves the way for designing novel spintronic devices based on strained silicene.