Probing spin-charge separation in a tomonaga-luttinger liquid

In a one-chmensionai (1D) system of interacting electrons, excitations of spin and cnarge travel at different speeds, according to the theory of a Tomonaga-Luttinger liquid (TLL) at low energies. However, the clear observation of this spin-charge separation is an ongoing challenge experimentally. We have fabricated an electrostatically gated ID system in which we observe spin-charge separation and also the predicted power-law suppression of tunneling into the ID system. The spin-charge separation persists even beyond the low-energy regime where the TLL approximation should hold. TLL effects should therefore also be important in similar, but shorter, electrostatically gated wires, where interaction effects are being studied extensively worldwide.