Is the Hofstadter energy spectrum observable in far-infrared absorption?

TL;DR

This paper investigates whether the Hofstadter energy spectrum can be observed through far-infrared absorption measurements in a modulated two-dimensional electron gas subjected to a magnetic field, using self-consistent calculations.

Contribution

It provides a theoretical analysis of the far-infrared absorption spectrum revealing signatures of the Hofstadter spectrum in a periodically modulated 2D electron gas.

Findings

Identification of intra- and intersubband magnetoplasmon modes

Observation of anticrossings with cyclotron resonance harmonics

Dependence of modes on the number of flux quanta per unit cell

Abstract

The far-infrared absorption of a periodically modulated two-dimensional electron gas in a perpendicular constant magnetic field is calculated self-consistently within the Hartree approximation. For vanishing modulation the magnetoplasmon dispersion shows simple anticrossings with harmonics of the cyclotron resonance, as expected. For increasing modulation we identify intra- and intersubband magnetoplasmon modes charaterized by the number of flux quanta through each unit cell of the periodic potential.