LIGHT AND CURRENT In molecular condution junctions 2014 CaSTL - PowerPoint PPT Presentation

A. Nitzan, Tel Aviv University LIGHT AND CURRENT In molecular condution junctions 2014 CaSTL Summer School, Irvine Thanks W. Belzig, A. Burin, B. Feinberg, M. Galperin, J. Gersten, O. Godsi, P. Hänggi, M. Jouravlev, S. Kohler, K. Kaasbjerg, Lehmann, G. Li, M. Oren, T. Seideman, M. Sukharev,

MOLECULAR JUNCTIONS

H OT SPOTS

MOLECULAR JUNCTIONS U x   B 1 /2 4 s     2  kL kR T ( E ) exp 2 m U ( ) x E dx T ( E )          B k  2  s 2   h % E E / 2 1              k kL kR J. G. Simmons, J. Appl. Phys. 1963 (cited by 2571)

e  Landauer I dE f ( E ) f ( E ) T ( E )      L R f ormula h   1  f ( E ) exp ( E ) / k T 1         K K B   e F e F T(E) f L (E) – f R (E) f L (E) – f R (E) T(E) I g Weber et al, Chem. Phys. 2002 F

INELSTIC ELECTRON TUNNELING SPECTROSCOPY h  V V  h  V

Light Scattering  in -  0  in  out incident scattered  in -  0  in  out h h 0 0    in -  0  in  out

Localization o f Inelastic Tunneling and the Determination o f Atomic-Scale Structure with Chemical Speci f icity B.C.Stipe, M.A.Rezaei and W. Ho, PRL, 82, 1724 (1999) STM image (a) and single-molecule vibrational spectra (b) o f three acetylene isotopes on Cu(100) at 8 K. The vibrational spectra on Ni(100)are shown in (c). The imaged area in (a), 56Å x 56Å, was scanned at 50 mV sample bias and 1nA tunneling current Recall: van Ruitenbeek et al (Pt/H 2 )- dips

D ephasing and relaxation are important Relative timescales are important Transient localization may be important Electron-vibration interactions may be important Interaction with light

R.M Hochstrasser and C. A. Nyi, J. Chem. Phys. 70, 1112 (1979) Azulene in Naphthalene matrix (4-35K)

M ol ec ular c ondu c tion mol ec ul e

MOLECULAR JUNCTIONS • F abri c ation • Stability • Chara c t e rization • F un c ionality • Control

M olecular electronics and plasmonics: The interaction of molecular conduction junctions with light

Junction spectroscopy (1) Local radiation f ield associated with the new boundary conditions (2) Sur f ace “selection rules”

(3) Finite li f etime f or electron on molecule (broadening due to electron trans f er interaction with metal)   kL kR T ( E )  k 2 2 % E E / 2            k kL kR

(4) Finite li f etime f or electronic excitation due to dipolar coupling (energy trans f er to e-h pairs in metal)

Junction spectroscopy (5) With bias – partial occupation may change absorption and scattering spectra (6) Current may drive light and light may drive current (7) Heat may develop and temperature change may a ff ect spectra

ABSORPTION LINESHAPE 2 e V   2 1 6 10 e V    P B B 0.1 e V   N L N R T 300 K  0.01 e V     ML ,1 MR ,1 0. 2 e V     ML , 2 MR , 2 Fig.2 The absorption current (photons/s). The molecular electronic levels are assumed pinned to the right electrode, i.e. the bias shi f ts upward the electronic states o f the le f t electrode.

Transfer Rates r l     1 { l } V 1 l V 1r 2 E 2 V 2     E 2 V ; K L R ,     1 R 1 r R          1 K 1 k K E E  r E E  k   1 L 1 R T ( E )  1 2 2 E E / 2            1 1 L 1 R = 1 if E=E 1 and G 1 L = G 1 R

V V V

L R { l } d 1 1 d  ~ e   larg e d  ~ c    d d   Ohm’s law!

D ependence on bridge length N e   1 1 1  k k N      up diff   Segal, AN, Davis, Wasielewski, Ratner J. Phys. Chem. B, 104, 3817-3829 (2000)

D NA (Giese et al 2001)

J. AM. CHEM. SOC. 132, 435(2010)

F RET ( F luorescence ( F orster) Resonance Energy Transfer) R 2   1 2 k ~ 3 R

1 1 dS ~  6 4 R R R 1 1 d V ~  6 3 R R

efficie n cy  1 n 1 r r /    0 F RET: n=6 SET : n=4

R>>Particle size 1 ~ Su r face A r ea dS  6 6 R R R 1 ~ pa rt ic l e vo l ume d V  6 6 R R

2 k ~  R t o t 2 3 k ~ d r E ; ~ Im    e n t    pa rt ic l e M. Sukharev, N. F reifeld and AN, J.Phys.Chem C, 2014

Electric field from an oscillating dipole in free space ik r ik r e 1 ik e r r r 2    E k n n 3n n                2   r r r   r  1 1 1   2 E ~ 1     2 2 4 r  k r k r         4 1 1   2 E ~    2 2 4 P r k r k r        

r r H D ynamical equations   = E ,  0 t  r r H   = E ,  0 t  r r r E   = H J ,   0 t  ˆ d ˆ ˆ  metal ˆ ˆ i = [ H , ] i h h     d t 2 r r ˆ ˆ p  ( ) = H = H d E t ( )     r 2   0 i molecules   r   r r r r J  2 = a J b E ; a = ; b = J P t     0 p    t r r r r  ˆ P = n  ; Tr       

M. Sukharev and AN Phys. Rev. A 84, 043802 (2011)

LIGHT ON JUNCTIONS

SWITCHES

Light operated molecular switch

NON RESONANCE EFFECTS

Nano Lett. 9, 1615 (2009)

RESONANCE EFFECTS

CHARGE TRANS F ER TRANSITIONS m g =7 D m e =31+ / -1.5 D m g =5.5 D m e =15.5+ / -1.5 D m g =7 D m e =30+ / -1.5 D S. N. Smirnov & C. L. Braun, REV. SCI. INST. 69, 28 75 ( 199 8)

Light induced current in molecular junctions -resonance mechanism LU M O | 2>  L  R HO M O |1 >

G G Curr e nt indu ce d light Int e nsity E 2 1 = 2e V Y i e ld M ,1 = G M , 2 =0.1 e V N =0.1 e V Obs e rvations: F la xe r e t al, S c i e n ce 2 6 2 , 2 01 2 ( 1993 ) , Qiu e t al, S c i e n ce 2 99 , 5 42 (2 003 ) , G. Hoffmann e t al, Phys. R e v. B 65, 2 1 2 107 (2 00 2)

Emission yield f rom 9-10 dichloroanthracene on a quartz lens coated with ITO (Indium Tin Oxide), a transparent conductor. Flaxer et all, Science, 262, 2012 (1993)

Wu, Nazin and H o, Phys. Rev. B 77, 205430 (2008) Inelastic tunneling spectrum of the same electronic transition observed Schematic sketch and S p atial d epe nd e n ce of th e on the left by its energy diagram of a STM e mission s pec tra from th e emission spectrum. junction, in which a single sam e mol ec ul e as in F ig. 2 . No vibrational magnesium porphine Th e lo c ations of th e ST M resolution can be MgP its molecular ti p wh e r e e a c h s pec trum achieved probably structure shown in was c oll ec t e d ar e mark e d in because many molecule is adsorbed on a th e ST M imag e of this vibrations contribute thin insulating alumina mol ec ul e ins e t. film grown on a NiAl110 surface.

Photon emission f rom biased junctions h  V V  h  V

Detector sensitivity

B. Fainberg and A . NitzanPR B, 76 , 245329 (2007) T he phase structure (chirp) of the pulse determines the temporal ordering of its different frequency components that enables us to control molecular dynamics.

| 1, w > V p | 2,0> | 1, w( t ) > | 1,0> t

Total electronic population inversion can be achieved using coherent light-matter interactions like adiabatic rapid passage (ARP), which is based on sweeping the pulse f requency through a resonance.

( ) t ( t t ) ( (      0  w 0 = e 2 - e 1

Raman Scattering anti-Stokes Stokes incident incident scattered scattered h h h h 0 0 0 0    