2D Metals: A "Dimensional Reduction Strike" in Materials Science!

The thickness of a 2D metal is merely 1 ångström (0.1 nanometer), equivalent to one-millionth the thickness of a standard A4 paper. If a 3-meter-long metal cube were compressed into a single atomic layer, its area would be sufficient to cover the entire city of Beijing. This extreme thinness causes drastic changes in the physical properties of metals—for instance, monolayer bismuth exhibits electrical conductivity over 10 times higher than its bulk counterpart, and its resistance can be tuned via electric fields, offering a novel approach to ultra-low-power chips.

For over a century, scientists widely believed that metals could not be made two-dimensional. This is because metal atoms are bound by strong metallic bonds, whereas traditional 2D materials (like graphene) rely on weak van der Waals forces between layers, allowing them to be easily peeled apart like a stack of pancakes. Metals, however, resemble "compressed biscuits," making it nearly impossible to isolate a single layer. This deadlock was only broken when a Chinese research team invented the "van der Waals extrusion technique."

The Core Technology: The Secret of the Atomic "Rolling Pin"

1. How to compress metal into an atomic sheet?
   The team's breakthrough lies in the "van der Waals extrusion technique":

   • Step 1: Heat the metal until molten, transforming it into a flowing atomic "dough."

   • Step 2: Use monolayer molybdenum disulfide (MoS₂) as a "nano rolling pin," sandwiching and extruding the molten metal from above and below.

   • Step 3: After cooling, a single atomic layer of metal is obtained. It is then encapsulated with MoS₂ for protection against oxidation and degradation.
     MoS₂, with its melting point exceeding 2692°C and excellent chemical stability, acts as an ideal "ultimate anvil."

Previous 2D materials were highly susceptible to oxidation and degradation. However, the Chinese team's encapsulation technology enables 2D metals to remain stable in ambient air for over a year with no performance degradation. This means they are no longer fragile "hot-house flowers" confined to the lab, but materials ready for real-world applications.

Application Prospects: A Cross-Domain Tech Revolution

1. Electronics: A "Game Changer" for the Chip Industry
   The ultra-thin nature of 2D metals can drastically reduce transistor size and power consumption. For example, using them for circuit interconnects could push beyond the physical limits of traditional manufacturing processes, potentially enabling 28nm lithography machines to produce chips with performance approaching 5nm nodes. Breakthroughs in high-frequency communication devices and transparent flexible displays are also anticipated.

2. Quantum Technology: Opening a "New Door" to the Microscopic World
   When metals are thinned down to just a few atomic layers, quantum effects dominate their properties. 2D metals will become a prime platform for studying quantum Hall effects, superconductivity, and topological phase transitions, potentially accelerating the practical realization of quantum computers.

3. Energy & Catalysis: A "Green Engine" for Soaring Efficiency
   The immense surface area of 2D metals could boost catalytic reaction efficiency by tens of times. Future applications include solar cells, hydrogen evolution catalysts, and CO₂ conversion devices. More remarkably, a car roof covered with a 2D metal film might potentially power the vehicle for a thousand kilometers after just two hours of sunlight exposure.

4. Military & Aerospace: "Sci-Fi Upgrades" for Soldier Gear
   Imagine soldiers' batteries shrinking from suitcase-sized to bandage-sized, or exoskeleton suits becoming as light as down jackets yet enabling humans to outrun cheetahs... These scenarios may no longer be distant dreams.

Reviewers at the journal Nature hailed this achievement as "pioneering the field of 2D metals" and "a landmark advance in materials science." What further astonished the international scientific community is that while previous breakthroughs in 2D materials (like graphene's discovery by a UK team) were largely led by Europe and the US, the breakthrough in 2D metals is the first to distinctly bear the "Made in China" label.