Dissipationless Quantum Spin Current at Room Temperature

While microscopic laws of physics are invariant under the reversal of thearrow of time, the transport of energy and information in most devices is anirreversible process. It is this irreversibility that leads to intrinsicdissipations in electronic devices and limits the possibility of quantumcomputation. We theoreticallypredict that the electric field can induce asubstantial amount of dissipationless quantum spin current at room temperature,in hole doped semiconductors such as Si, Ge and GaAs. Based on a generalizationof the quantum Hall effect, the predicted effect leads to efficient spininjection without the need for metallic ferromagnets. Principles found in thiswork could enable quantum spintronic devices with integrated informationprocessing and storage units, operating with low power consumption andperforming reversible quantum computation.