Tight-Binding Model
Square: E(k) = -2t₁[cos(kₓ)+cos(k_y)] - 4t₂cos(kₓ)cos(k_y)
Van Hove singularities: saddle points where ∇_k E = 0
Perfect nesting: Q=(π,π) → divergent χ(Q) → magnetism
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Square: E(k) = -2t₁[cos(kₓ)+cos(k_y)] - 4t₂cos(kₓ)cos(k_y)
Van Hove singularities: saddle points where ∇_k E = 0
Perfect nesting: Q=(π,π) → divergent χ(Q) → magnetism
—