Linewidth Study of Electric Dipole induced Spin Resonance in Uniaxially Stressed n-InSb for Far-Infrared Region: Theoretical

Abstract

Experimental investigation on electric dipole induced ESR in n-InSb was reported in the preceding paper (Experimental). Far-infrared laser with λ=220 µ m∼84 µ m and the samples with N D - N A =10 15 cm -3 were employed in the experiment. In this article we mainly focus our attentions to the origin of the observed linewidth. Linewidth is nearly constant at low temperature and increases with T above ∼20 K: 0.02 Tesla at 4.2 K and 0.1 Tesla at 60 K. From the relation of \(|g^{\ast}|\mu_{\rm B}\Delta H=\hbar/T_{1}\), we obtain T 1 ∼10 -12 sec at T =60 K, where | g * |=44 is obtained from the absorption data for λ=119 µm. Such a short relaxation time T 1 cannot be expected from any spin-lattice relaxation process. Rashba-Sheka's Hamiltonian: H ′ =δ 0 ( E ) σ·κ , σ : Pauli spin matrix, κ x = k y k x k y - k z k x k z etc. , is responsible for the linewidth broadening. This interaction stems from the lack of inversion symmetry in InSb. Linewidth calculation based on the Kubo-Tomita's theory qualitatively explain...