Researchers have discovered a new class of two-dimensional (2D) metals that exhibit both superconductivity and itinerant magnetism, two phenomena that are usually mutually exclusive. These exotic metals could potentially be used for building and co-designing the next generation of programmable quantum devices.
What are 2D metals and why are they important?
2D metals are materials that consist of thin layers of atoms arranged in a regular pattern. They have unique physical properties that differ from their bulk counterparts, such as high electrical conductivity, enhanced magnetism, and unconventional superconductivity.
Superconductivity is the ability of a material to carry an electrical current with zero resistance, which means no energy loss or heat generation. Itinerant magnetism is a type of magnetism that arises from the collective motion of electrons, rather than from their fixed positions on atoms.
Superconductivity and itinerant magnetism are usually incompatible, as the former requires the pairing of electrons with opposite spins, while the latter tends to align them in the same direction. However, some materials can exhibit both phenomena under certain conditions, such as low temperatures, high pressures, or strong interactions.
These materials are of great interest for quantum technologies, as they can enable the creation of novel quantum states and devices, such as superconducting qubits, spintronics, and topological insulators.
How did the researchers find the new 2D metals?
The researchers were part of the Quantum Systems Accelerator (QSA), a multi-institutional collaboration led by Lawrence Berkeley National Laboratory (Berkeley Lab) and Sandia National Laboratories. The QSA aims to build and co-design the next generation of programmable quantum devices that can solve challenging problems in science, engineering, and society.
The researchers focused on a new type of 2D metal called NiTa4Se8, which belongs to a family of transition metal dichalcogenides (TMDs). TMDs are compounds that consist of a layer of transition metal atoms sandwiched between two layers of chalcogen atoms (such as sulfur, selenium, or tellurium).
NiTa4Se8 has a unique structure that combines two different types of TMDs: one with strongly correlated electrons that move in 2D planes, and another with ferromagnetic layers of nickel atoms. The researchers hypothesized that this combination could result in interesting electronic behaviors, such as superconductivity and itinerant magnetism.
To test their hypothesis, the researchers performed a series of experiments using state-of-the-art facilities and instruments at Berkeley Lab, such as the Advanced Light Source (ALS) and the Molecular Foundry. They also collaborated with scientists from Los Alamos National Laboratory, who provided theoretical support and computational simulations.
The experiments involved measuring the electronic structure, magnetic properties, and transport characteristics of NiTa4Se8 samples at various temperatures and magnetic fields. The results confirmed that NiTa4Se8 exhibits both superconductivity and itinerant magnetism in a narrow temperature range around 10 Kelvin (-263 degrees Celsius).
What are the implications and challenges of the discovery?
The discovery of superconductivity and itinerant magnetism in NiTa4Se8 opens up new possibilities for exploring and manipulating quantum phenomena in 2D metals. The researchers hope that their findings will inspire further studies on other TMDs with similar structures and properties.
One of the potential applications of these 2D metals is to use them as building blocks for complex superconducting quantum processors. These processors could perform quantum computations faster and more efficiently than current technologies, as well as enable new functionalities such as error correction and fault tolerance.
However, there are also many challenges and limitations that need to be overcome before these 2D metals can be used for practical purposes. For instance, the researchers need to understand how to control and optimize the superconductivity and magnetism in these materials, as well as how to integrate them with other components and devices.
Another challenge is to find ways to increase the operating temperature of these 2D metals, as they currently require extremely low temperatures to exhibit their quantum properties. This would make them more compatible with existing technologies and reduce the cost and complexity of cooling systems.
The researchers plan to continue their investigations on NiTa4Se8 and other TMDs with the help of QSA partners and resources. They also hope to collaborate with other scientists and engineers who are interested in developing new quantum devices based on these exotic 2D metals.
