Electron spin resonance–scanning tunneling microscopy experiments on thermally oxidized Si(111)

Manassen, Yishay; Ter-Ovanesyan, Evgeny; Shachal, D.; Richter, Shachar

doi:10.1103/physrevb.48.4887

Cited by 51 publications

(30 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…50,51 We can therefore assume that the actual T 1 for the molecules of BDPA and DPPH deposited on Au͑111͒ will be a value in the range of 1 -42 s. This situation does not apply to the Pb centers that were previously investigated by ESN-STM from one of the authors. 31 Indeed T 1 for paramagnetic impurities in a semiconductor is much longer than for BDPA and DPPH. This implies that the actual enhancement of the nuclear lon-gitudinal spin flip rate would be much reduced in a semiconductor as compared with our samples.…”

Section: Discussionmentioning

confidence: 98%

“…These results prove and extend previous experiments by Durkan and Welland 1 but also point out the difficulty of this experiment. We have employed a method of detection designed by Manassen et al 31 and improved it and applied it to the case of physisorbed organic radicals. We give a detailed explanation of our experimental setup to allow interested scientists to have a good starting point to develop their own instrumentation.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Spin noise fluctuations from paramagnetic molecular adsorbates on surfaces

Messina

Mannini

Caneschi

et al. 2007

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Spin noise fluctuations from paramagnetic molecular adsorbates on surfaces

Messina

Mannini

Caneschi

et al. 2007

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The results predict a rapid increase of the linewidth with the field. The linewidths calculated are too broad which indicates [23] while the lower curve for BDPA molecules [39] that there must be correlations between the times of the tunneling events due to Coulomb repulsion. We think that linewidth measurements can provide a lot of information on the temporal nature of the tunneling process.…”

Section: Random Samplingmentioning

confidence: 99%

“…When a tip of an STM is located above a paramagnetic spin center (in the presence of an external magnetic field) the tunneling current is modulated by the precession. It was shown [22,23] that the AC current at the Larmor frequency is spatially localized within 0.5 − 1nm. It is the spatial localization that indicates (though it must be proved) that this technique is capable of detecting a single spin.…”

Section: −1mentioning

confidence: 99%

1/f Spin noise and a single spin detection with STM

Manassen

Balatsky

2004

Israel Journal of Chemistry

View full text Add to dashboard Cite

We propose a novel mechanism for single spin detection based on the 1/f spin current noise. We postulate the 1/f spin noise for the tunneling current, similar to the ubiquitous 1/f noise in magnetic systems. Magnetic coupling between tunneling electrons and localized spin S then leads to the peak at Larmor frequency in the power spectrum of the electric current fluctuations I 2 ω . The elevated noise in the current spectrum will be spatially localized near the magnetic site. The difference in the power spectra taken at the Larmor frequency and elsewhere would reveal the peak in the spectrum. We argue that signal to noise ratio for this mechanism is on the order one.In addition we discuss the asymmetric lineshapes observed regularly with this measurement. We show that such lineshapes are in accordance to the random sampling done with the tunneling electrons. Yet, this predicts a linewidth at least one order of magnitude larger than observed experimentally which is likely to be due to electrostatic repulsion between the tunneling electrons and temporal correlations in the tunneling process. 1/F SPIN NOISEThe phenomenon of 1/f (flicker) noise is known for almost 80 years [1]. It describes the deviation from the flat spectral density expected from a current made of uncorrelated charge carriers -at low frequencies. In this range, the spectral density was found to obey a power law of the form 1/f α where f is the frequency, and α = 0.5 − 1.5. Flicker noise appears in endless number of electronic devices, in music [2] in ocean streams [3,4] and in many entirely different systems. This is one of the most universal phenomena, yet, one of the largest enigmas in physical sciences.An early explanation to this phenomenon was that the 1/f noise can arise from a superposition of relaxation processes [5]. In this model the noise is described as a superposition of consecutive random events, each starts at a certain time t 0 and follow a simple exponential relaxation law: N (t − t 0 ) = N 0 e −(t−t0)/τ . The power spectrum of one such event is a Lorentzian. The power spectrum of a large number of such consecutive random events, all with the same τ is also a Lorentzian. If, on the other hand, there is a distribution of relaxation times P (τ ) ∼ 1/τ , from τ 1 to τ 2 than the overall spectral density will obey a power law ∼ 1/f in the range between τ −1 1 and τ −1 2 . A common denominator to many mechanisms proposed for different 1/f phenomena [6,7] is a distribution of relaxation times.1/f noise is ubiquitous in STM tunneling current although its origins are a source of continuous mystery that is not fully understood until now [8,9,10,11]. Unlike the well known shot noise 1/f noise is proportional to the square of the current such that: I 2 (ω) /I 2 = const. Where I 2 (ω) is the spectral density of current fluctuations (in units of A 2 /Hz) and I is the current. Empirically, the current fluctuations in 1/f noise are known to obey the Hooge formulawhere N are the number of current carriers in the sample and a is of the order of 0....

show abstract

“…In this method, a Larmor frequency component of the tunneling current is induced by the precession of a nearby single spin on the surface. The existence of this phenomenon has been demonstrated on several spin systems, allowing also observation of hyperfine coupling 1, [10][11][12][13][14][15][16][17][18][19] . We note that the theoretical understanding of the phenomena seen in ESR-STM is a subject of ongoing research 1,20 .…”

Section: Introductionmentioning

confidence: 99%

Fingerprints of single nuclear spin energy levels using STM – ENDOR

Manassen

Averbukh

Jbara

et al. 2018

Journal of Magnetic Resonance

View full text Add to dashboard Cite

We performed STM-ENDOR experiments where the intensity of one of the hyperfine components detected in ESR-STM is recorded while an rf power is irradiated into the tunneling junction and its frequency is swept. When the latter frequency is near a nuclear transition a dip in ESR-STM signal is observed. This experiment was performed in three different systems: near surface SiC vacancies where the electron spin is coupled to a next nearest neighbor 29 Si nucleus; Cu deposited on Si(111)7x7 surface, where the unpaired electron of the Cu atom is coupled to the Cu nucleus ( 63 Cu, 65 Cu) and on Tempo molecules adsorbed on Au(111), where the unpaired electron is coupled to a Nitrogen nucleus ( 14 N). While some of the hyperfine values are unresolved in the ESR-STM data due to linewidth we find that they are accurately determined in the STM-ENDOR data including those from remote nuclei, which are not detected in the ESR-STM spectrum. Furthermore, STM-ENDOR can measure single nuclear Zeeman frequencies, distinguish between isotopes through their different nuclear magnetic moments and detect quadrupole spectra. We also develop and solve a Bloch type equation for the coupled electron-nuclear system that facilitates interpretation of the data. The improved spectral resolution of STM -ENDOR opens many possibilities for nanometric scale chemical analysis.

show abstract

Electron spin resonance–scanning tunneling microscopy experiments on thermally oxidized Si(111)

Cited by 51 publications

References 20 publications

Spin noise fluctuations from paramagnetic molecular adsorbates on surfaces

Spin noise fluctuations from paramagnetic molecular adsorbates on surfaces

1/f Spin noise and a single spin detection with STM

Fingerprints of single nuclear spin energy levels using STM – ENDOR

Contact Info

Product

Resources

About