PHYSICS/BK21 SEMINAR[09.08.05]
관련링크
본문
"
Readout of single electron spins in a micro-magnet
Double-quantum-dot using charge sensing techniques
ØSpeaker : Dr. Yun-Sok Shin [Tokyo University]
ØPlace : Physics Seminar Room (Science Bldg, 3-201)
ØDate & Time : Aug, 5 (Wed), 16:00 ~ 17:00 pm
Abstract
Electron spins in semiconductors has been attracted in recent research of quantum information
processing by their long coherence and scalability [1,2]. An individual electron spin provides two
quantum states implementing a quantumbit (qubit), fundamental unit of quantum computers.
Realization of qubits requires to manipulate and readout spins. Magnetic resonance was recently
demonstrated to coherently manipulate individual electron spins in semiconductor quantum dots.
As for spin readout, single-shot readout has been experimentally realized in a QD by spin-to-charge
conversion scheme [3,4] and the readout of spins in a double quantum dot (DQD) has been
theoretically proposed in various ways.
Photon assisted tunneling (PAT) is a powerful technique to readout the spin. PAT allows selective
resonance tunneling of the spin when plunged in a slanting Zeeman field. In order to realize spin readout,
we adopt a double quantum dot configuration with a quantum point contact (QPC) for non-destructive
charge sensing readout. The stray magnetic field from the micro-magnet integrated with the DQD
provides different Zeeman energies for each dot. This lifts off the spin degeneracy of PAT between the
two dots. Matching the frequency of PAT enables either spin-up or spin-down electron to transit from
one dot to the other. The PAT-induced charge delocalization within the double-dot is then detected by
the QPC charge sensor.
We demonstrated continuous spin readout in a micro-magnet DQD. We observed the PAT transitions
between two states with the same spin of the two-dot with charge sensing techniques. The PAT shows
the two peaks as a function of the microwave frequency, whose difference is consistent with the
estimated Zeeman energy from the micro-magnet. These PAT transitions are spin addressable as a
function of external magnetic fields.
Contact Person : Prof. Hu-Jong Lee(054-279-2072, hjlee@postech.ac.kr)"
Readout of single electron spins in a micro-magnet
Double-quantum-dot using charge sensing techniques
ØSpeaker : Dr. Yun-Sok Shin [Tokyo University]
ØPlace : Physics Seminar Room (Science Bldg, 3-201)
ØDate & Time : Aug, 5 (Wed), 16:00 ~ 17:00 pm
Abstract
Electron spins in semiconductors has been attracted in recent research of quantum information
processing by their long coherence and scalability [1,2]. An individual electron spin provides two
quantum states implementing a quantumbit (qubit), fundamental unit of quantum computers.
Realization of qubits requires to manipulate and readout spins. Magnetic resonance was recently
demonstrated to coherently manipulate individual electron spins in semiconductor quantum dots.
As for spin readout, single-shot readout has been experimentally realized in a QD by spin-to-charge
conversion scheme [3,4] and the readout of spins in a double quantum dot (DQD) has been
theoretically proposed in various ways.
Photon assisted tunneling (PAT) is a powerful technique to readout the spin. PAT allows selective
resonance tunneling of the spin when plunged in a slanting Zeeman field. In order to realize spin readout,
we adopt a double quantum dot configuration with a quantum point contact (QPC) for non-destructive
charge sensing readout. The stray magnetic field from the micro-magnet integrated with the DQD
provides different Zeeman energies for each dot. This lifts off the spin degeneracy of PAT between the
two dots. Matching the frequency of PAT enables either spin-up or spin-down electron to transit from
one dot to the other. The PAT-induced charge delocalization within the double-dot is then detected by
the QPC charge sensor.
We demonstrated continuous spin readout in a micro-magnet DQD. We observed the PAT transitions
between two states with the same spin of the two-dot with charge sensing techniques. The PAT shows
the two peaks as a function of the microwave frequency, whose difference is consistent with the
estimated Zeeman energy from the micro-magnet. These PAT transitions are spin addressable as a
function of external magnetic fields.
Contact Person : Prof. Hu-Jong Lee(054-279-2072, hjlee@postech.ac.kr)"
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