The physicists found that kagome flat bands remain separated at high temperatures, indicating that localized electrons drive the material’s magnetism.
Researchers are gaining new insights into magnetism and
electronic interactions in advanced materials.
The findings of a team at Rice University could
revolutionize fields like quantum computing and high-temperature
superconductors.
Their study of iron-tin (FeSn) thin films change how
scientists view kagome magnets, which are named after a traditional
basket-weaving pattern. The team discovered that FeSn’s magnetic properties
come from localized electrons, not the previously assumed mobile electrons.
According to the team, the findings challenge existing
theories about kagome metals and offer new insights into magnetism, potentially
guiding the creation of materials with customized properties for advanced
technologies like quantum computing and superconductors.
“This work is expected to stimulate further experimental and
theoretical studies on the emergent properties of quantum materials, deepening
our understanding of these enigmatic materials and their potential real-world
applications,” said Ming Yi, an associate professor of physics and astronomy
and Rice Academy Senior Fellow, in a statement.
Exploring kagome magnetism
Kagome magnets, named after a traditional basket-weaving
pattern, are materials featuring a distinct lattice-like structure. This design
enables them to exhibit unique magnetic and electronic behaviors, which arise
from the quantum destructive interference of electronic wave functions.
Studying the interplay of structure, electron interactions,
and magnetism is made possible by magnetic kagome materials. Numerous magnetic
kagome system types have been reported, such as the RMn6Sn6 family (where R is
a rare earth element) and the binary FemXn family (where X is Sn or Ge).
Magnetic kagome materials are exciting for studying how magnetism, interactions, and structure work together. Many types of magnetic kagome systems have been discovered, such as the FemXn family (where X can be Sn or Ge) and the RMn6Sn6 family (with R being a rare earth element).
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An image of a powerful quantum CPU on a PCB motherboard with
data transfers. |
In these materials, specific energy levels called kagome
flat bands are close to a key energy level known as the Fermi level when they
are not magnetically ordered. It is believed that partially filling these flat
bands could lead to a type of magnetism called Stoner-type ferromagnetism.
However, scientists have not yet been able to observe the
magnetic splitting that occurs at higher temperatures in these materials,
leaving questions about how magnetism works in kagome magnets.
Advancing quantum technologies
In their new research, the team produced high-quality FeSn
thin films and examined their electrical structure using a sophisticated method
that combines molecular beam epitaxy and angle-resolved photoemission
spectroscopy.
They discovered that the kagome flat bands stayed divided
even at high temperatures, a sign that the material’s magnetism is driven by
localized electrons. Understanding how electron behavior affects magnetic
characteristics in kagome magnets is made more difficult by the electron
correlation effect.
According to researchers, the work also provided a new
understanding of how electron interactions affect the behavior of kagome
magnets by revealing that certain electron orbitals had greater interactions
than others, a process known as selective band renormalization that has been
seen in iron-based superconductors.
“Our study highlights the complex interplay between
magnetism and electron correlations in kagome magnets and suggests that these
effects are non-negligible in shaping their overall behavior,” said Zhen Ren, a
Rice Academy Junior Fellow, in a statement.
The team also claims the study has wider ramifications for
materials with comparable characteristics and furthers our understanding of
FeSn.
New technologies like topological quantum computation, where
the interaction of magnetism and topological flat bands creates quantum states
that can be utilized as quantum logic gates, and high-temperature
superconductors may benefit from an understanding of flat bands and electron
correlations.
The details of the team’s research were published in the journal Nature Communications.