Affiliation:
1. National Key Laboratory of Spintronics Hangzhou International Innovation Institute Beihang University Hangzhou 311115 China
2. Fert Beijing Institute School of Integrated Circuit Science and Engineering Beihang University Beijing 100191 China
3. Hefei Innovation Research Institute Beihang University Hefei 230013 China
4. Laboratoire Albert Fert CNRS Thales Université Paris‐Saclay Palaiseau 91767 France
Abstract
AbstractOrbitronic devices operate by manipulating orbitally polarized currents. Recent studies have shown that these orbital currents can be excited by femtosecond laser pulses in a ferromagnet such as Ni and converted into ultrafast charge currents via orbital‐to‐charge conversion. However, the terahertz emission from orbitronic terahertz emitters based on Ni is still much weaker than that of the typical spintronic terahertz emitter. Here, this work reports a more efficient light‐induced generation of orbital current from a CoPt alloy, and the terahertz emission from CoPt/Cu/MgO is comparable to that of benchmark spintronic terahertz emitters. By varying the composition of the CoPt alloy, the thickness of Cu, and the capping layer, this work confirms that THz emission primarily originates from the orbital accumulation generated within CoPt, propagating through Cu, followed by subsequent orbital‐to‐charge conversion due to the inverse orbital Rashba‐Edelstein effect at the Cu/MgO interface. This study provides strong evidence for the efficient orbital current generation in CoPt alloy, paving the way for efficient orbital terahertz emitters.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China