The interplay between topology and magnetism has a bright future

Date:
March 2, 2022
Source:
Max Planck Institute for Chemical Physics of Solids
Summary:
A new review paper on magnetic topological materials introduces
the new theoretical concept that interweave magnetism and topology.



FULL STORY ==========================================================================
The new review paper on magnetic topological materials of Andrei Bernevig, Princeton University, USA, Haim Beidenkopf, Weizmann Institute of Science, Israel, and Claudia Felser, Max Planck Institute for Chemical Physics
of Solids, Dresden, Germany, introduces the new theoretical concept
that interweave magnetism and topology. It identifies and surveys
potential new magnetic topological materials, mentions their possible
future applications in spin and quantum electronics and as materials
for efficient energy conversion.

The review discusses the connection between topology, symmetry and
magnetism at a level suitable for graduate students in physics, chemistry
and materials science that have a basic knowledge of condensed matter
physics.


========================================================================== Magnetic topological materials represent a class of compounds whose
properties are strongly influenced by the topology of the electronic wavefunctions coupled with their spin configuration. Topology is a
simple concept dealing with the surfaces of objects. The topology of a mathematical structure is identical if it is preserved under continuous deformation. A pancake has the same topology as a cube, a donut as a
coffee cup, and a pretzel as a board with three holes.

Adding spin offers additional structure -- a new degree of freedom -- for
the realization of new states of matter that are not known in non-magnetic materials. Magnetic topological materials can support chiral channels of electrons and spins, and can be used for an array of applications from information storage, control of dissipationless spin and charge transport,
to giant responses under external stimuli such as temperature and light.

The review summarizes the theoretical and experimental progress
achieved in the field of magnetic topological materials beginning
with the theoretical prediction of the Quantum Anomalous Hall Effect
without Landau levels, and leading to the recent discoveries of magnetic
Weyl semimetals and antiferromagnetic topological insulators. Recent theoretical progress that resulted in the tabulation of all magnetic
symmetry group representations and topology is outlined. As a result
of this, all known magnetic materials - - including future discoveries
-- can be fully characterized by their topological properties. The identification of materials for a specific technological application
(e.g. Quantum Anomalous Hall) is straightforward.

Using this approach magnetic topological materials with magnetic
transition temperatures above room temperature can be identified or if necessary, designed for classical applications such as thermoelectric
devices, Hall sensors or efficient catalysts but they are also useful for quantum applications at low temperatures, including computing and sensing.

Andrei Bernevig comments that "The realization of the QAHE at room
temperature would be revolutionary, overcoming limitations of many
data-based technologies, which are affected by power losses from Joule heating," and his colleague Stuart Parkin, Max PIanck Institute of Microstructure Physics, Halle, Germany, "can imagine how the novel
properties of this new class of magnetic materials can pave the way to
new generations of low energy consuming quantum electronic and spintronic devices and even novel superconducting spintronic devices." Claudia
Felser, MPI CPfS is most excited about their potential applications
in chemistry. She says "if we can design a magnetic catalyst for water splitting we might be able to change the catalytic properties with an
external field, which would allow us to switch on and off catalysis." For
Haim Beidenkopf, the quantum computer is perhaps the most exciting
direction in science today: "The design of a material that exhibits a high temperature quantum anomalous Hall via quantum confinement of a magnetic
Weyl semimetal, and its integration into quantum devices is my main goal
for the future." The field of magnetic topological materials clearly
has and will have impact in both the scientific and technological worlds.

========================================================================== Story Source: Materials provided by Max_Planck_Institute_for_Chemical_Physics_of_Solids.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. B. Andrei Bernevig, Claudia Felser, Haim Beidenkopf. Progress and
prospects in magnetic topological materials. Nature, 2022; 603
(7899): 41 DOI: 10.1038/s41586-021-04105-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220302113059.htm

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