Experimental studies of Coulomb drag between ballistic quantum wires

The Coulomb drag between two spatially separated one-dimensional (1D) electron systems in lithographically fabricated 2 mum long quantum wires is studied experimentally. The drag voltage V-D shows peaks as a function of a sate voltage which shifts the position of the Fenni level relative to the 1D subbands. The maximum in V-D and the drag resistance R-D occurs when the 1D subbands of the wires are aligned and the Fermi wave vector is small, The drag resistance is found to decrease exponentially with interwire separation. In the temperature region 0.2 K less than or equal to T less than or equal to 1 K, R-D decreases with increasing temperature in a power-law fashion R-D alpha T-x with x ranging from -0.6 to -0.77 depending on the gate voltage. We interpret our data in terms of the Tomonaga-Luttinger liquid theory.