Using light pulses, scientists have made electricity and magnetism 'ghost' through a material in directions that should be physically impossible.
April 14, 2026
Original Paper
Ultrafast ghost Hall states in a 2d altermagnet
arXiv · 2604.11361
The Takeaway
This 'ghost Hall effect' in altermagnets allows for spin and charge to move orthogonally without traditional Hall physics. It enables the creation of ultra-fast electronics that can process information using laser pulses instead of slow, heat-generating currents.
From the abstract
Two-dimensional materials that exhibit optically active spin and valley degrees of freedom represent one of the most fascinating -- and potentially most technologically useful -- platforms for the ultrafast interaction of light and matter. Here we show, via the example of Cr$_2$SO, that two dimensional altermagnets host valley states controllable by femtosecond laser light: linearly polarized light pulses excite charge at one of two inequivalent valleys, with which valley charge is excited at de