Title: Electrical control of a single Mn atom in a QD
1Electrical control of a single Mn atom in a QD
J. Fernández-Rossier
Department of Applied Physics, U. Alicante SPAIN
February 2006
University of Alicante, Spain
www.ua.es/personal/jfrossier/
2(No Transcript)
3Outline
Single EXCITON Spectroscopy
CdTe QD 1 Mn
CdTe QD
CdTe QD 1 Mn1 e
L. Besombes et al., PRL 93, 207403, 04
Y. Léger et al., PRL 97,07401 (06)
L. Besombes et al., PRL 93, 207403, 04
- Optics QD Hamiltonian for 1 Mn electrons
holes - Transport single ELECTRON Spectroscopy
- Magnetism Mn 1 hole single atom nanomagnet
International Workshop on Quantum-Dot
Spintronics December 7-8, 2006, Ruhr-Universität
Bochum, Germany
4PEOPLE
R. Aguado
L. Brey
Y.Leger L.BesombesL.Maingault H.Mariette
Laboratoire de Spectrométrie Physique, GRENOBLE,
France. Equipe CEA-CNRS Nanophysique et
Semi-conducteurs Laboratoire Louis Néel, CNRS
GRENOBLE, France.
5Background
6Single exciton in Mn-doped II-VI QD
ZnSe QD many Mn
CdTe QD 1 Mn
CdTe QD many Mn
10 meV
A. A. Maksimov, et al., Phys. Rev. B 62, R7767
(00)
L. Besombes et al., PRL 93, 207403, 04
G. Bacher et al. PRL. 89, 127201 (2002)
7Neutral CdTe QD 1 Mn
6 Lines
CdTe QD 1 Mn
L. Besombes et al., PRL 93, 207403, 04
THEORY J. Fernández-Rossier, PRB73, 045301 (06)
8Basic Notions
Cd 3d10 4s2 Mn 3d5 4s2
Mn replaces Cd Mn2
Mn2 S5/2, 2S16
EXCHANGE INTERACTIONS
SPIN DENSITY
- Mn - CB electron
- Mn - VB hole
- Mn-Mn Short range AF
QD affects both SYMMETRY and Amplitude
9Basic Notions Q0 states
Size of Hilbert space6
np0
10Basic Notions Q-1 states
Size of Hilbert space12
n1, p0
S2
Heisenberg
S3
SSeM
11Basic Notions Q1 states
Size of Hilbert space12
Mz,Sz
n0, p1
Ising
12Q0 EXCITON states
6 Doublets
Size of Hilbert space24
13EXCITON states
a
a
a
Photon polarizationMn spin polarization
Size of Hilbert space24
14EXCITON states
b
a
b
b
Size of Hilbert space24
15EXCITON states
Photon Energy Polarization Mn spin measurement
Size of Hilbert space24
16Full theory Single exciton spectroscopy (1 Mn
dot)
EXPERIMENTS Y. Léger et al. PRL 95, 047403 (05)
WE UNDERSTAND ehMn
THEORY J. Fernández-Rossier, PRB73, 045301 (06)
17Charged CdTe QD 1Mn
11 Lines
Vb
Gated CdTe QD 1 Mn
Y. Léger, L. Besombes, J. Fernández-Rossier, L.
Maingault, H. Mariette PRL 97,07401 (06)
18Charged exciton states (1 Mn dot). Q-1
PL diagram
Trion State
12 Trion States
Full Shell
a
b
b
Exp.
a
a
S2
b
S3
12 ground states
19Charged exciton states (1 Mn dot). Q1
PL diagram
Ground State
Trion State
12 Trion States
Full Shell
Q1
Q1
Loosely bound Hole
Small Jh
12 ground states
20Electrical Control of the Ground State spin
Ground State
Ground State
Full Shell
Q0
Q1
Q-1
21Electrical Control of the Ground State spin
Ground State
Ground State
Full Shell
Nanomagnet
Paramagnet
Superparamagnet
Ising
Heisenberg
S2
S3
22Single Electron Transport
VG
I
Vb
- Electrically tunable nanomagnet
- Probing the magnetism upon current flow.
Single Electron transport in Tunable nanomagnets
JFR, R. Aguado, cond-mat/0604437
23Related Work
Remanent Zero Field Spin Splitting of Self
Assembled QD.., C. Gould et al. Phys. Rev. Lett.
97, 017202 (06)
24Theory Single electron transport
Same Hamiltonian than OPTICS
STATES WITH a FIXED NUMBER of CARRIERS
COMPUTE RATES. SPIN FRANK-CONDON
Obtain QD density matrix SOLVE MASTER EQUATION
for Vg and Vb, T
Compute Charge, Current, Spin
25QD STATES
GATE CONTROL of single atom Magnetic Anisotropy
ST
Mz
Ising
Heisenberg
ZXX
Free
HH
LH
Q-1
Q0
Q1
Q3
26Transport Hysteretic Linear Conductance
Vb
I?0
I0
VG
N-1
N
N1
27Reminder of Coulomb Blockade
E
Q2
Q1
Q0
VG
Q
G
Q2
Q1
Q0
VG
28Charging curves for the Mn-doped dot
CB electron
VB Hole
3 PEAKS instead of 1 !!
Standard Results
HYSTERESIS in G0
29Hole injection in the Mn-doped dot
No spin flip T1? (sim.) T1gt1ms (exp)
30Some LH-HH Mixing 2 peaks and Hysteretic
Charging curves
2 Peaks when for Realistic value of spin flip
Small spin flip T1? (sim.) T1gt1ms (exp)
31Hysteretic Charging curve for LH
Hysteresis For in-plane easy axis
No spin flip T1? (sim.) T1gt1ms (exp)
32Finite Bias zero field spin splitting
Vb
I?0
I0
VG
N-1
N
N1
33Inelastic single spin spectroscopy electrons
ZERO FIELD SPLITTING
EXP
S2
S3
S2
S3
C. Gould et al. Phys. Rev. Lett. 97, 017202 (06)
34Inelastic single spin spectroscopy holes
35CHARGED Mn-doped QD NANOMAGNET
Vb
36ERGODIC MAGNETISM 1Mn 1hole
MAGNETIC ANISOTROPY
Nanomagnet
Ising
37Mn1h NANOMAGNET
Spectrum (meV)
Initial State
Mn T110ms MnHole???
ltMgt
Non Ergodic Magnetization
Remanence and Hysteresis
38OUTLOOK QD AMPLIFIES the Mn spin quantum state
104 CdTe atoms 1 Mn
5nm
L. Besombes et al., PRL 93, 207403, 04
39CONCLUSIONS
CdTe QD 1 Mn
Measuring the quantum state of a single spin
Electrical Tuning of the MAE of a single atom
Hysteretic Linear Conductance
Y. Léger,L. Besombes, J. Fernández-Rossier, L.
Maingault, H. Mariette PRL 97,07401 (06)
JFR, R. Aguado, cond-mat/0604437
www.ua.es/personal/jfrossier/
40Thanks for your attention
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