国家自然科学基金委员会数理学部实验物理讲习班

国家自然科学基金委员会 

数理学部实验物理讲习班 

单分子隧道谱 & 原子分子操纵 

裘晓辉 

国家纳米科学中心



Scanning Tunneling Microscopy (STM) 

Key issues: 

Extremely small mechanical vibration 

Extremely precise motion control 

I ∝ V exp( −Φ 

1/ 2 

s 

)



Scanning Tunneling Microscopy (STM) 

- Seeing is believing 

Key issues: 

Extremely small mechanical vibration 

Extremely precise motional control 

Si(111) 7x7 reconstruction 

Binnig, G., Rohrer, H., Gerber, Ch., & Weibel, E. Physical Review Letters 49, 1 (1982a): 57-60



单分子隧道谱



Scanning Metal-Insulator-Metal: Tunneling Spectroscopy Tunneling Spectroscopy 

(STS) 

Pyrex Al 

oxide 

10 10 molecules 

Al 

I 

= 

4πe 

h 

eV 

∫ 

0 

I = 

[ ] 2 

ρ ( E − eV + ε ) ρ ( E + ε ) M dε 

s 

f 

F 

Z 

T 

( x, 

y, 

z, 

V 

proposed in 1985 by G. Binnig, et al. 

) 

F



dI/dV spectroscopy: superconductor, Kondo, etc. 

I 

∝ 

eV 

∫ 

0 

ρ ( E 

s 

F 

dI 

dV 

− eV + ε ) ρ ( E 

T 

F 

∝ ρ ( E − eV ) 

s 

F 

+ ε ) dε



E f 

dI/dV spectroscopy: molecular orbitals 

V bias 

sample 

LUMO 

HOMO 

tip 

Vbias < 0,负偏压 

检测样品的电子占据态 

E f 

φ LUMO 

sample φtip 

sample tip 

HOMO 

V bias = 0 

E f 

V bias 

sample 

LUMO 

HOMO 

tip 

E f 

Vbias > 0,正偏压 

检测样品的电子空态 

Internal degrees of freedom a molecule: 

spin, translation, rotation, vibration, electronic



d 2 I/dV 2 spectroscopy: 

Inelastic Electron Tunneling Spectroscopy 

Substrate



A single molecule STS : instrumentation 

Ultra-high Vacuum: 

Low Temperature: 

base pressure:



Single molecule vibrational spectroscopy: 

C2H2 on Cu(100) 

Science, Vol. 280, 1732 (1998), Stipe, Rezaei, and Ho



Chemical specificity at SM level: STM-IETS 

Phys. Rev. Lett. 81, 1263-1266 (1998)



Electron induced molecular rotation 

e



Single molecule vibrational spectroscopy:



STM-IETS spectroscopy: the practical procedure 

• instrumentation: low temp 

• tip preparation: spatial resolution vs. energy resolution 

• lock-in: power spectrum, bias modulaion 

• data analysis: polarity symmetry, background subtraction 

Tunneling Current 

2 2 

2 

W = WI 

+ ( 1. 

7Vac) 

+ ( 5. 

4kBT 

/ e 

0 

V bias 

) 

2 

I( 

t) 

= 

V ( t) 

= V 

f ( V ( t)) 

0 

I( 

t) 

= f ( V0 

) + 

12 

3 

I 

+ Asin( 

ωt) 

0 

∫ 

d ( f ( V ( t)) 

dV dV 

123 

dI 

dV



CuPc on Al 2 O 3 /NiAl(110) 

Phys. Rev. Lett., Vol. 93, 196806(2004)



dI/dV of CuPc



Molecular orbital of CuPc 

LUMO 

HOMO



Scanning tunneling spectroscopy of CuPc on oxide



A upclose view:



Franck-Condon Principle 

• Spin 

• Translational 

• Rotational 

• Vibrational 

• Electronic } Vibronic States



Vibronic excitation of CuPc: macrocyle, isoindole 

* 

* 

J. Phys. Chem, Vol. 90, 569 (1986)



Vibronic state mediated electron transport 

LUMO 

involved 

HOMO 

involved



单原子分子的STM操纵



Creatures of the Nano World -- Atoms 

Example: Carbon Atom 

proton 

neutron 

nucleus 

6 protons 

6 neutrons



2 1S Electrons 

4 2P Electrons 

nucleus



2 1S Electrons 

4 2P Electrons 

5 Carbon Atoms 

1 Nanometer



X 1000 

1 Micrometer 

X 1000 

1 Millimeter 

1 Nanometer 

1 Nanometer 

1 Micrometer 

100,000,000 typical atoms



A giant in a small world



Electron induced molecular rotation 

e



Standing waves in a two-dimensional electron gas



the smallest Au chain: where the orbital comes? 

6s- 

6s 6s 6s 6s band 6s 6s structure 

6s+



the smallest Au chain: where the orbital comes?



Pull or Push ?



A single molecule mechanics: van der Waals interaction



A single molecule mechanics: electron & electric field 

Tunneli ng current (nA) 

Tunneling current (nA) 

4 

3 

2 

1 

0 

-1 

1.8V -1.8V -1.8V 1.8V 

-1.8V -1.8V 1.8V 1.8V -1.8V 1.8V 

Sample Bias (V) 

0.5 

-1.0 

-0.39 0 0.39 0.78 1.17 

∆ Z ( Å ) 

-2 

LUMO-involved 

-2.0 -1.5 -1.0 Sa -0.5 mpl e 0.0 0.0Bi as 0.5 ( V) 1.0 1.5 2.0 

process 

Sample Bias (V) 

1.5 

1.0 

-1.5 

-2.0 

- 

+ 

I II 

II I 

+ 

-



How sharp an Xenon would be?



CO manipulation: vibrational multiexcitation 

R = 

Stipe, et al. Phys. Rev. Lett. 78, 4410 (1997) 

d 

Bartels, Meyer, Rieder, Phys. Rev. Lett. 80, 2004 (1998) 

I 

N



Metal carbonyl: Single Bond Formation & Characterization 

H.J. Lee and W. Ho, Science 286, 1719 (1999)



Construction of a visible Au-CuPc-Au “junction” 

Science, Vol. 302, 77 (2003)



An artificial single molecule junction 

Science, Vol. 302, 77 (2003)



dI/dV images of a single molecule junction:



Single molecule chemical reaction



Manipulation of Au adatom by a Voltage/Current Pulse 

• Shape of STM image changed 

reversibly by voltage pulse and 

tunneling current 

• Manipulated adatom scatter 

interface state with no bound 

states and is repelled by positive 

sample bias => 

Negatively Charged !? 

• Both states are stable and have 

different diffusion coefficients 

Au atom on NaCl bilayer supported by a Cu(111) surface



IBM PC : with a inside 

molecular cascade



Spectroscopy 

(electronic, vibrational) 

Imaging 

(atomic or sub-molecular 

resolution) 

Manipulation 

(mechanical, electric field, 

low energy electrons)



谢谢!



Scanning Tunneling Microscopy 

– Imaging, Spectroscopy, Manipulation 

Atomic structure of Si(111) Quantum corral 

Single molecule vibrational spectroscopy: STM-IETS 

Molecular cascade 

© IBM corporation

国家自然科学基金委员会数理学部实验物理讲习班

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