Universal Mechanism of Spin Relaxation in Solids

Conventional elastic theory ignores internal local twists and torques. Meantime, spin-lattice relaxation is inherently coupled with local elastic twists through conservation of the total angular momentum (spin + lattice). This coupling gives universal lower bound (free of fitting parameters) on the relaxation of the atomic or molecular spin in a solid [1] and on the relaxation of the electron spin in a quantum dot [2]. \newline \newline [1] E. M. Chudnovsky, D. A. Garanin, and R. Schilling, Phys. Rev. B \textbf{72}, 094426 (2005). \newline [2] C. Calero, E. M. Chudnovsky, and D. A. Garanin, Phys. Rev. Lett. \textbf{95}, 166603 (2005).