Bosonization approach to charge and spin dynamics of one-dimensional spin-1/2 fermions with band curvature in a clean quantum wire

Sofian Teber (1, 2)

1 NEEL - ThQC - Théorie Quantique des Circuits
2 ICTP - Abdus Salam International Centre for Theoretical Physics [Trieste]

We consider one-dimensional spin-1/2 fermions in a clean quantum wire, with forward scattering interactions and a nonlinear single-particle spectrum ξk = v͉lk͉l + k^2/2m, where v is the Fermi velocity and 1 / m is the band curvature. We calculate the dynamical structure factor ͑DSF͒ of the model at small wave vector q with the help of the bosonization technique. For spinless fermions, we show that, starting from the single-parametric spectrum ω = u͉lq͉l bosonization emulates the two-parametric excitation spectrum ω = u͉lq͉l ± q^2/2m * , where m * decreases with increasing repulsive interactions. Moreover, away from the excitation cone, i.e.ω>> u͉lq͉l, bosonization yields the two-pair excitation continuum of the DSF. For spinful fermions, we show that the spin-charge coupling (SCC) due to band curvature affects the charge and spin DSFs in an asymmetric way. For the charge DSF, SCC manifests as a two-peak structure: a charge peak at = u ͉q͉ but also a spin peak at ω = uρlq͉l, as charge fluctuations may decay via chargeless spin-singlet excitations. For the magnetic DSF, SCC manifests as a continuous transfer of magnetic spectral weight to frequencies ω > uσlq͉l, as spin fluctuations decay via pairs of chargeless spin and spinless charge-neutral excitations.

Domaines: Matière Condensée [cond-mat]

Sofian Teber. Bosonization approach to charge and spin dynamics of one-dimensional spin-1/2 fermions with band curvature in a clean quantum wire. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2007, 76 (4), pp.045309. ⟨10.1103/PhysRevB.76.045309⟩. ⟨hal-01697268⟩