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Electrically induced ambipolar spin vanishments in carbon nanotubes.

Matsumoto D, Yanagi K, Takenobu T, Okada S, Marumoto K - Sci Rep (2015)

Bottom Line: Carbon nanotubes (CNTs) exhibit various excellent properties, such as ballistic transport.The field-induced ESR technique is suitable for microscopic investigation because it can directly observe spins in the CNTs.We observed a clear correlation between the ESR decrease and the current increase under high charge density conditions, which directly demonstrated electrically induced ambipolar spin vanishments in the CNTs.

View Article: PubMed Central - PubMed

Affiliation: Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.

ABSTRACT
Carbon nanotubes (CNTs) exhibit various excellent properties, such as ballistic transport. However, their electrically induced charge carriers and the relation between their spin states and the ballistic transport have not yet been microscopically investigated because of experimental difficulties. Here we show an electron spin resonance (ESR) study of semiconducting single-walled CNT thin films to investigate their spin states and electrically induced charge carriers using transistor structures under device operation. The field-induced ESR technique is suitable for microscopic investigation because it can directly observe spins in the CNTs. We observed a clear correlation between the ESR decrease and the current increase under high charge density conditions, which directly demonstrated electrically induced ambipolar spin vanishments in the CNTs. The result provides a first clear evidence of antimagnetic interactions between spins of electrically induced charge carriers and vacancies in the CNTs. The ambipolar spin vanishments would contribute the improvement of transport properties of CNTs because of greatly reduced carrier scatterings.

No MeSH data available.


Related in: MedlinePlus

Anisotropy of the ESR signal of the SWCNT thin film.Angular dependence of the g value (a) and ΔH1/2 (b) of the ESR signal of the SWCNT thin film on H relative to the substrate at 50 K.
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f4: Anisotropy of the ESR signal of the SWCNT thin film.Angular dependence of the g value (a) and ΔH1/2 (b) of the ESR signal of the SWCNT thin film on H relative to the substrate at 50 K.

Mentions: Finally, we present the anisotropy of the ESR signal in the direction of the external magnetic field H relative to the substrate to investigate the anisotropy of the spin-orbital interaction in the SWCNT thin film. The measurements were performed at 50 K to improve the SN ratio of the ESR signal. Figure 4a,b show the anisotropy of the g value and ΔH1/2 of the ESR signal, respectively, where θ is defined as the angle between H and the normal of the substrate (Fig. 1a). Clear anisotropy of the g value and ΔH1/2 is observed for the first time in the ESR studies of CNTs. Solid lines in Fig. 4a,b show the least-squares fits with the following fitting curves for the observed g value and ΔH1/2, respectively:


Electrically induced ambipolar spin vanishments in carbon nanotubes.

Matsumoto D, Yanagi K, Takenobu T, Okada S, Marumoto K - Sci Rep (2015)

Anisotropy of the ESR signal of the SWCNT thin film.Angular dependence of the g value (a) and ΔH1/2 (b) of the ESR signal of the SWCNT thin film on H relative to the substrate at 50 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493558&req=5

f4: Anisotropy of the ESR signal of the SWCNT thin film.Angular dependence of the g value (a) and ΔH1/2 (b) of the ESR signal of the SWCNT thin film on H relative to the substrate at 50 K.
Mentions: Finally, we present the anisotropy of the ESR signal in the direction of the external magnetic field H relative to the substrate to investigate the anisotropy of the spin-orbital interaction in the SWCNT thin film. The measurements were performed at 50 K to improve the SN ratio of the ESR signal. Figure 4a,b show the anisotropy of the g value and ΔH1/2 of the ESR signal, respectively, where θ is defined as the angle between H and the normal of the substrate (Fig. 1a). Clear anisotropy of the g value and ΔH1/2 is observed for the first time in the ESR studies of CNTs. Solid lines in Fig. 4a,b show the least-squares fits with the following fitting curves for the observed g value and ΔH1/2, respectively:

Bottom Line: Carbon nanotubes (CNTs) exhibit various excellent properties, such as ballistic transport.The field-induced ESR technique is suitable for microscopic investigation because it can directly observe spins in the CNTs.We observed a clear correlation between the ESR decrease and the current increase under high charge density conditions, which directly demonstrated electrically induced ambipolar spin vanishments in the CNTs.

View Article: PubMed Central - PubMed

Affiliation: Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.

ABSTRACT
Carbon nanotubes (CNTs) exhibit various excellent properties, such as ballistic transport. However, their electrically induced charge carriers and the relation between their spin states and the ballistic transport have not yet been microscopically investigated because of experimental difficulties. Here we show an electron spin resonance (ESR) study of semiconducting single-walled CNT thin films to investigate their spin states and electrically induced charge carriers using transistor structures under device operation. The field-induced ESR technique is suitable for microscopic investigation because it can directly observe spins in the CNTs. We observed a clear correlation between the ESR decrease and the current increase under high charge density conditions, which directly demonstrated electrically induced ambipolar spin vanishments in the CNTs. The result provides a first clear evidence of antimagnetic interactions between spins of electrically induced charge carriers and vacancies in the CNTs. The ambipolar spin vanishments would contribute the improvement of transport properties of CNTs because of greatly reduced carrier scatterings.

No MeSH data available.


Related in: MedlinePlus