A new method for creating real 2D layers of metals like bismuth, gallium, indium, tin, and lead was revealed by a team of Chinese researchers

This may open the path for future quantum and electronic technologies, such as topological insulators.

Quantum Dot and Quantum Confinement

– Quantum Dot: A semiconductor particle just a few nanometers in size; functions like a “giant atom” because of limited electron movement.

– Quantum Confinement: When the movement of electrons is limited to a confined area, energy levels become discrete, much like in atoms.

Materials with Low Dimensions

• A material is characterized as 1D or 2D based on the degree to which it restricts its electrons.
• 2D metals consist of extremely thin layers of metal atoms, typically only 1–2 atoms thick, allowing electrons to move solely in two dimensions.
• Graphene is a well-known two-dimensional substance: It is made up of a single layer of carbon atoms interconnected in a hexagonal arrangement.
• The electrons within this sheet are confined to motion in two dimensions, hence 2D.
• Consequently, they act as if they lack mass, leading to characteristics not observed in other substances.

Obstacles in Producing 2D Metals

In contrast to carbon, which readily forms two-dimensional sheets (graphene), metal atoms tend to bond in three-dimensional structures.

Efforts to create atom-thin metal sheets have mostly been unsuccessful or resulted in sheets that are merely a few nanometers thick — excessive for genuine quantum confinement.

Innovative Approach: The 2D Sandwich Method

Metal powder is heated between MoS₂-coated sapphire plates and pressed under 200 million Pa pressure, creating ultra-thin layers — similar to bismuth, measuring just 6.3 Å thick (approximately two atoms deep).

Why Are 2D Metals Important?

Anticipated Characteristics:

Topological Insulator: Conducts electricity solely at the edges, not throughout the surface.

Nonlinear Hall Effect: Produces voltage at right angles when exposed to electric field.

Field Effect Adjustability: Electrical conductivity modulated by external fields.

Uses:

• Highly sensitive sensors (medical/military).
• Quantum computing with high efficiency.
• Next-generation electronic and photonic technologies.