Electron-phonon effects on spin-orbit split bands of two-dimensional systems

Abstract

The electronic self-energy is studied for a two dimensional electron gas coupled to a spin-orbit Rashba field and interacting with dispersionless phonons. For the case of a momentum independent electron-phonon coupling (Holstein model) we solve numerically the self-consistent non-crossing approximation for the self-energy and calculate the electron mass enhancement m * /m and the spectral properties. We find that, even for nominal weak electron-phonon interaction, for strong spin-orbit couplings the electrons behave as effectively strongly coupled to the phonons. We interpret this result by a topological change of the Fermi surface occurring at sufficiently strong spin-orbit coupling, which induces a square-root divergence in the electronic density of states at low energies. We provide results for m * /m and for the density of states of the interacting electrons for several values of the electron filling and of the spin-orbit interaction.

Spin and angle resolved photoemission on non-magnetic low-dimensional systems

“…This region is of special interest because if the simple Rashba model holds, here the density of states (DOS) ν(E F ) shows a one-dimensional Van Hove singularity ν(E F ) ∼ (E 0 − E F ) −1/2 in the limit E F → E 0 , which can also be detected by scanning tunnelling spectroscopy (STS) [65]. Bringing this singularity to the Fermi level is expected to have profound influence on the electron-phonon interaction [66] and, for relevant systems, on the superconducting transition temperature [67]. Fig.…”

Strongly enhanced electron-phonon coupling in the Rashba-split state of the Bi/Ag(111) surface alloy

“…31,32 If it is close to the Fermi energy, the singularity can be expected to have a pronounced influence on the system's properties. In particular, it can influence the strength of the effective electron-phonon coupling 32 and facilitate the transition to the superconducting state.…”

Phonon-drag thermopower and hot-electron energy-loss rate in a Rashba spin–orbit coupled two-dimensional electron system

“…One can also increase the strength of the spin-orbit coupling with the help of an external gate voltage 9,10 . The RSOI modifies various properties [11][12][13][14][15] of a 2DES including the electron polaron effective mass, polaron binding energy, mobility, etc. The electron-phonon interaction (EPI) plays an important role in determining transport properties of a 2DES.…”