  Magnetic solitons offer functionalities as information carriers in multiple
spintronic and magnonic applications. However, their potential for nanoscale
energy transport has not been revealed. Here we demonstrate that
antiferromagnetic solitons, e.g. domain walls, can uptake, transport and
release energy. The key for this functionality resides in their relativistic
kinematics; their self-energy increases with velocity due to Lorentz
contraction of the soliton and their dynamics can be accelerated up to the
effective speed of light of the magnetic medium. Furthermore, their
classification in robust topological classes allows to selectively release this
energy back into the medium by colliding solitons with opposite topology. Our
work uncovers important energy-related aspects of the physics of
antiferromagnetic solitons and opens up the attractive possibility for
spin-based nanoscale and ultra-fast energy transport devices.
