Atomtronic Datta-Das transistor using ultracold Strontium atoms

We report experimental demonstration of atomtronic Datta-Das transistor in free space with ultracold strontium atoms as the (spin) carriers. Datta-Das transistor is a device in which the spin current from source to drain is controlled by the gate voltage similar to a conventional FET where electric charge current from source to drain is controlled by the gate voltage. In the experiment, we simulate a beam of spin-polarized atoms passing through a gate region made of three gaussian beams coupled to a tripod-like energy level scheme and control their final spin orientation. We use the ratio of Rabi frequencies of the tripod lasers as the gate parameter, the analogue of the gate voltage, to characterize the atomtronic Datta-Das transistor. We show that the spin rotation can be well controlled and it is robust to a wide range of velocities of the atoms. We also discuss about the sensitivity of the spin rotation with the gate parameter to the geometry of the laser beams.