Fig. 2: Ballistic orbital transport in Ni/Pt heterostructure.

a Terahertz signal emitted from Ni(3 nm) /Pt(x nm) heterostructure with variable Pt thickness x = 3, 6, 9, and 18; Inset shows the zoomed-in peak of the THz pulse indicating a right shift as we increase the Pt thickness. b Terahertz signal emitted from NiFe (3 nm) /Pt (x nm) heterostructure with variable Pt thickness with x = 1, 2, 4, 6, and 8 indicating no right shift in the peak. c Linear delay in the emitted THz pulse with an increase in Pt thickness demonstrating the ballistic orbital transport in Ni/Pt heterostructure in contrast to spin transport in NiFe/Pt heterostructure. d Chirping of the emitted THz pulse with an increase in Pt thickness in Ni/Pt heterostructure providing evidence of the increase in the angular dispersion of the transport entity, proving the longer relaxation length of orbital current in contrast to spin transport in NiFe/Pt heterostructure.