An incompressible state of a photo-excited electron gas

TL;DR

This paper investigates the formation of an incompressible electronic state in a photo-excited electron gas, revealing new quantum states induced by resonant photon absorption at weak magnetic fields.

Contribution

It demonstrates the emergence of an incompressible electron state under resonant photo-excitation, expanding understanding of quantum Hall phenomena beyond strong magnetic fields.

Findings

Incompressible state observed under weak magnetic fields

Dissipation-less transport achieved via photon absorption

Resonant excitation leads to new quantum states

Abstract

Two dimensional electrons in a magnetic field can form new states of matter characterized by topological properties and strong electronic correlations as displayed in the integer and fractional quantum Hall states. In these states the electron liquid displays several spectacular characteristics which manifest themselves in transport experiments with the quantization of the Hall resistance and a vanishing longitudinal conductivity or in thermodynamic equilibrium when the electron fluid becomes incompressible. Several experiments have reported that dissipation-less transport can be achieved even at weak, non-quantizing magnetic fields when the electrons absorb photons at specific energies related to their cyclotron frequency. Compressibility measurements on electrons on liquid helium demonstrate the formation of an incompressible electronic state under these resonant excitation conditions.