Charge Oscillations Emerging after Application of an Intense Light Field to Superconductors on a Dimer Lattice

TL;DR

This study investigates charge oscillations in superconducting dimer lattice systems after intense light pulses, revealing different oscillation modes depending on interaction strength and their dependence on system parameters.

Contribution

It introduces a detailed analysis of charge-oscillation modes in superconductors on a dimer lattice, highlighting the emergence of distinct modes based on interaction strength.

Findings

Weak attraction: electronic breathing mode.

Strong attraction: pair breathing mode.

Intermediate attraction: a distinct oscillation mode.

Abstract

Motivated by recent experimental findings for an organic superconductor, charge oscillations that emerge after a strong pulse of an oscillating electric field is applied are studied in electron systems in a superconducting phase on a lattice with a dimerized structure. They are analyzed using Fourier spectra of charge densities whose time profiles are obtained by numerically solving the time-dependent Schr\"odinger equation within a mean-field approximation. Depending on the strengths of attractive interactions, different charge-oscillation modes appear. For weak attractions, the charge-oscillation mode is an electronic breathing mode, which was previously found for repulsive interactions. For strong attractions, it is a pair analog of the electronic breathing mode (a `pair' breathing mode). For intermediate attractions, it is another mode whose transient current distributions are considerably different from those of the breathing modes. We investigate how their frequencies and amplitudes depend on interactions and transfer integrals.