Imaging tunable Luttinger liquid systems in van der Waals heterostructures

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• One-dimensional (1D) interacting electrons exhibit unique properties distinct from higher-dimensional Fermi liquids, often described as Luttinger liquids.
• Experimental characterization of 1D electron systems is challenging due to complex intra- and inter-chain interactions.
• Van der Waals heterostructures offer a platform for novel electronic phenomena.

Purpose of the Study:

• To demonstrate that layer-stacking domain walls (DWs) in van der Waals heterostructures can form a tunable Luttinger liquid system.
• To investigate the evolution of DW Luttinger liquids under varying interaction regimes.
• To explore new quantum phases arising from intra- and inter-chain interactions in periodic DW arrays.

Main Methods:

• Utilized scanning tunnelling microscopy (STM) to image DW Luttinger liquids.
• Tuned interaction regimes by controlling electron density.
• Analyzed the structural and electronic properties of DWs in isolated and coupled arrays.

Main Results:

• Observed Wigner crystallization in single DWs at low carrier density, consistent with a spin-incoherent Luttinger liquid.
• Identified dimerized Wigner crystals at intermediate densities due to magneto-elastic coupling.
• Discovered new quantum phases in periodic DW arrays, including a 2D electron crystal and an electronic smectic liquid crystal phase.

Conclusions:

• Layer-stacking DWs in 2D heterostructures provide a versatile platform for realizing and tuning Luttinger liquid behavior.
• The study reveals novel quantum phases driven by the interplay of intra- and inter-chain interactions.
• This work opens new opportunities for exploring fundamental 1D electron physics in engineered material systems.