NCTS (South)


DATE2012-10-15

TIME12:10

PLACER49223, Second Physics Building , NCKU

FIELDQuantum Information Science

SPEAKER Dr. Kuei-Lin Chiu - Cavendish Laboratory, Unviersity of Cambridge

TITLECharge pumping in graphene quantum dots

ABSTRACTThe high-speed, high-accuracy transport of single electrons in nanoscale devices is predicted to underpin future electronics. Charge pumping, which refers to a device that can shuttle n electrons per circle to give the quantised current I=nef, provides an exquisite way to link the electrical current to the elementary charge e and frequency f. Pumps based on lithographically-fixed tunnel barriers in mesoscopic metallic systems and normal/superconducting hybrid turnstiles can reach very small error rates, but only at MHz pumping speeds corresponding to small currents of the order 1 pA. Here we present a monolithic, fixed barrier single electron pump made entirely from graphene. We demonstrate pump operation at frequencies up to 1.4 GHz, and predict the error rate to be as low as 0.01 parts per million at 90 MHz. Our pumps can be tested against quantum pumping concepts and also pave the way towards the high frequency manipulation of charge required for developing graphene spin qubits.