Tunable Luttinger Liquid Systems in Van der Waals Heterostructures Imaged by Scanning Tunneling Microscopy

Core Concepts

Layer-stacking domain walls in van der Waals heterostructures form a broadly tunable Luttinger liquid system, exhibiting exotic quantum phenomena that can be characterized using scanning tunneling microscopy.

Abstract

The content discusses the experimental observation and characterization of Luttinger liquid behavior in one-dimensional (1D) electron systems formed by layer-stacking domain walls (DWs) in van der Waals heterostructures.

Key highlights:

• 1D interacting electrons in materials can exhibit exotic quantum phenomena that can be tuned by intra- and inter-chain electronic interactions.
• The authors demonstrate that DWs in van der Waals heterostructures form a broadly tunable Luttinger liquid system, including both isolated and coupled arrays.
• Using scanning tunneling microscopy, they imaged the evolution of DW Luttinger liquids under different interaction regimes tuned by electron density.
• At low carrier density, single DWs are highly susceptible to Wigner crystallization, consistent with a spin-incoherent Luttinger liquid.
• At intermediate densities, dimerized Wigner crystals form due to enhanced magneto-elastic coupling.
• Periodic arrays of DWs exhibit an interplay between intra- and inter-chain interactions, leading to new quantum phases:
  • At low electron densities, inter-chain interactions dominate, inducing a 2D electron crystal composed of phase-locked 1D Wigner crystals in a staggered configuration.
  • At higher densities, intra-chain fluctuation potentials dominate, resulting in an electronic smectic liquid crystal phase with algebraical correlation decay along the chain direction but disorder between chains.
• The work demonstrates that layer-stacking DWs in 2D heterostructures provide opportunities to explore Luttinger liquid physics.

Stats

One-dimensional (1D) interacting electrons are often described as a Luttinger liquid.
Luttinger liquids have properties that are intrinsically different from those of Fermi liquids in higher dimensions.

Quotes

"Here we demonstrate that layer-stacking domain walls (DWs) in van der Waals heterostructures form a broadly tunable Luttinger liquid system, including both isolated and coupled arrays."
"Single DWs at low carrier density are highly susceptible to Wigner crystallization consistent with a spin-incoherent Luttinger liquid, whereas at intermediate densities dimerized Wigner crystals form because of an enhanced magneto-elastic coupling."
"Periodic arrays of DWs exhibit an interplay between intra- and inter-chain interactions that gives rise to new quantum phases."

Key Insights Distilled From

Imaging tunable Luttinger liquid systems in van der Waals heterostructures - Nature

by Hongyuan Li,... at www.nature.com 07-03-2024

https://www.nature.com/articles/s41586-024-07596-6

Deeper Inquiries

How can the insights from this study on Luttinger liquid behavior in van der Waals heterostructures be applied to develop novel electronic devices or quantum technologies?

The insights gained from studying Luttinger liquid behavior in van der Waals heterostructures can be instrumental in the development of novel electronic devices and quantum technologies. By understanding how the tunable Luttinger liquid systems behave under different interaction regimes, researchers can potentially harness these unique properties for applications in quantum computing, spintronics, and nanoelectronics. For instance, the ability to manipulate the electron density to induce different quantum phases in these systems could lead to the development of new types of electronic devices with enhanced functionalities and performance characteristics.

What other types of 1D electron systems, beyond domain walls in van der Waals materials, could exhibit similar tunable Luttinger liquid behavior?

Apart from domain walls in van der Waals materials, other types of 1D electron systems that could exhibit similar tunable Luttinger liquid behavior include semiconductor nanowires, carbon nanotubes, and quantum wires in heterostructures. These systems possess confined geometries that promote strong electron-electron interactions, leading to the emergence of Luttinger liquid behavior. By manipulating parameters such as carrier density, magnetic field, or external gating, researchers can tune the properties of these 1D electron systems and explore a wide range of quantum phases and phenomena.

What are the potential implications of the observed electronic smectic liquid crystal phase for our understanding of strongly correlated electron systems in low dimensions?

The observed electronic smectic liquid crystal phase in the van der Waals heterostructures provides valuable insights into the behavior of strongly correlated electron systems in low dimensions. This phase, characterized by ordered electron arrangements along the chain direction but disorder between chains, highlights the delicate balance between intra- and inter-chain interactions in 1D electron systems. Understanding the properties of the electronic smectic phase can shed light on the nature of quantum correlations, phase transitions, and collective phenomena in low-dimensional materials. Moreover, this phase could serve as a model system for studying the interplay between electronic ordering and disordering processes, offering new perspectives on the behavior of strongly correlated electrons in confined geometries.