Optical manipulation of electronic dimensionality in a quantum material

TL;DR

This paper demonstrates a method to induce transient two-dimensional electronic states in a three-dimensional quantum material using femtosecond laser pulses, revealing potential for creating novel phases like light-induced superconductivity.

Contribution

It introduces a novel optical approach to generate and study transient 2D electronic states in 3D materials, expanding possibilities for quantum phase engineering.

Findings

Creation of macroscopic 2D domain walls with exotic properties

Observation of a potential light-induced superconductivity signature

Real-time dynamics captured by advanced spectroscopy techniques

Abstract

Exotic phenomenon can be achieved in quantum materials by confining electronic states into two dimensions. For example, relativistic fermions are realised in a single layer of carbon atoms, the quantized Hall effect can result from two-dimensional (2D) systems, and the superconducting transition temperature can be enhanced significantly in a one-atomic-layer material. Ordinarily, 2D electronic system can be obtained by exfoliating the layered materials, growing monolayer materials on substrates, or establishing interfaces between different materials. Herein, we use femtosecond infrared laser pulses to invert the periodic lattice distortion sectionally in a three-dimensional (3D) charge density wave material, creating macroscopic domain walls of transient 2D ordered electronic states with exotic properties. The corresponding ultrafast electronic and lattice dynamics are captured by time- and angle-resolved photoemission spectroscopy and MeV ultrafast electron diffraction. Surprisingly, a novel energy gap state, which might be a signature of light-induced superconductivity, is identified in the photoinduced 2D domain wall near the surface. Such optical modulation of atomic motion is a new path to realise 2D electronic states and will be a new platform for creating novel phases in quantum materials.