Optically anisotropic infinite cylinder above an optically anisotropic half space: Dispersion interaction of a single-walled carbon nanotube with a substrate

Šiber, Antonio; Rajter, Rick F.; French, Roger H.; Ching, W. Y.; Parsegian, V. Adrian; Podgornik, Rudolf

doi:10.1116/1.3416904

Cited by 9 publications

(9 citation statements)

References 11 publications

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“…The distance dependence of Casimir-Lifshitz interac-tions is further complicated by retardation screening of high frequency contributions at larger separations. The interplay of dielectric functions can lead to a rich variety of unusual effects, as demonstrated in [25,26]. However, we emphasize that the effects we demonstrate here are distinct from those that rely on particular combinations of dielectric materials.…”

Section: (8a)mentioning

confidence: 53%

Casimir-Lifshitz Torque Enhancement by Retardation and Intervening Dielectrics

Somers

Munday

2017

Phys. Rev. Lett.

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We investigate two effects that lead to a surprising increase in the calculated Casimir-Lifshitz torque between anisotropic, planar, semi-infinite slabs. Retardation effects, which account for the finite speed of light, are generally assumed to decrease the strength of Casimir-Lifshitz interactions. However, the nonretarded approximation underestimates the Casimir-Lifshitz torque at small separations by as much as an order of magnitude. Also, Casimir-Lifshitz forces are typically weakened with the insertion of an intervening dielectric. However, a dielectric medium can increase the short-range Casimir-Lifshitz torque by as much as a factor of 2. The combined effects of retardation and an intervening dielectric dramatically enhance the Casimir-Lifshitz torque in the experimentally accessible regime and should not be neglected in calculation or experimental design.

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Section: (8a)mentioning

confidence: 53%

Casimir-Lifshitz Torque Enhancement by Retardation and Intervening Dielectrics

Somers

Munday

2017

Phys. Rev. Lett.

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“…The cases of larger and very large separations between two SWCNTs and between a SWCNT and a planar substrate have been dealt with in our other publications that also contain full derivations for all separation limits 34,34,36,82 . Our analysis is strictly applicable only in the limit of infinitely long SWC-NTs; for a consistent analysis of finite size effects and ideal metallic static dielectric response one needs to consider an exact general multiple scattering formulation of the vdW -Ld interactions, such as derived by Emig and coworkers 83 .…”

Section: Hamaker Coefficientmentioning

confidence: 99%

“…In general at a finite mutual angle of the dispersion anisotropy axes θ the vdW interactions are codified by two values of the Hamaker coefficient, i.e. A (0) and A (2) , whereas in the parallel geometry they are given by a single value 34,34,36,82 .…”

Section: Hamaker Coefficientmentioning

confidence: 99%

Chirality-dependent properties of carbon nanotubes: electronic structure, optical dispersion properties, Hamaker coefficients and van der Waals–London dispersion interactions

Rajter¹,

French²,

Ching³

et al. 2013

RSC Adv.

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Optical dispersion spectra at energies up to 30 eV play a vital role in understanding the chirality-dependent van der Waals London dispersion interactions of single wall carbon nanotubes (SWCNTs). We use one-electron theory based calculations to obtain the band structures and the frequency dependent dielectric response function from 0-30 eV for 64 SWCNTs differing in radius, electronic structure classification, and geometry. The resulting optical dispersion properties can be categorized over three distinct energy intervals (M, π, and σ, respectively representing 0-0.1, 0.1-5, and 5-30 eV regions) and over radii above or below the zone-folding limit of 0.7 nm. While π peaks vary systematically with radius for a given electronic structure type, σ peaks are independent of tube radius above the zone folding limit and depend entirely on SWCNT geometry. We also observe the so-called metal paradox, where a SWCNT has a metallic band structure and continuous density of states through the Fermi level but still behaves optically like a material with a large optical band gap between M and π regions. This paradox appears to be unique to armchair and large diameter zigzag nanotubes. Based on these calculated one-electron dielectric response functions we compute and review Van der Waals -London dispersion spectra, full spectral Hamaker coefficients, and van der Waals -London dispersion interaction energies for all calculated frequency dependent dielectric response functions. Our results are categorized using a new optical dielectric function classification scheme that groups the nanotubes according to observable trends and notable features (e.g. the metal paradox ) in the 0-30 eV part of the optical dispersion spectra. While the trends in these spectra begin to break down at the zone folding diameter limit, the trends in the related van der Waals -London dispersion spectra tend to remain stable all the way down to the smallest single wall carbon nanotubes in a given class. IntroductionSince their discovery in 1993 by the Iijima and the Bethune groups 1,2 , single wall carbon nanotubes (SWCNTs) have received enthusiastic attention. Their intriguing mechanical and electrical properties make them ideal for a wide range of applications, from metal oxide semiconductor field effect transistors (MOSFETs) to novel drug delivery systems 3-8 and have inspired strong scientific and industrial interest 1,[9][10][11][12][13][14][15] . The area that has arguably received the most attention and focus is † Electronic Supplementary Information (ESI) available: [details of any supplementary information available should be included here]. See ) * In the context of the dielectric response functions of CNTs, we denote the SWCNT with a mnemonic [n,m, type] rather then the standard but equivalent (n,m), when we want to invoke its type explicitly in order to help the reader organize the voluminous information and in order to be consistent with our previous publications. Of course the two designations, together with the simple (n-m)/3 = integer rule to...

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“…To calcualte the Casimir interaction between a nanorod and a birefringent plate, we follow the method in Ref. [17,38] by assuming that a half space is a dilute assembly of anisotropic cylinders. With that we could extract the interaction between a cylinder and one semi-infinite half space from the interaction free energy between two half spaces.…”

Section: Casimir Interactionmentioning

confidence: 99%

“…Besides the linear momentum, the angular momentum carried by virtual photons can generate the Casimir torque (or van der Waals torque) for anisotropic materials [11][12][13]. Despite significant interests about the van der Waals and Casimir torque [14][15][16][17][18][19][20][21][22], the torque has not been measured experimentally though it was predicted over 40 years ago, mainly due to the lack of a suitable tool [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Detecting Casimir torque with an optically levitated nanorod

2017

Phys. Rev. A

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The linear momentum and angular momentum of virtual photons of quantum vacuum fluctuations can induce the Casimir force and the Casimir torque, respectively. While the Casimir force has been measured extensively, the Casimir torque has not been observed experimentally though it was predicted over forty years ago. Here we propose to detect the Casimir torque with an optically levitated nanorod near a birefringent plate in vacuum. The axis of the nanorod tends to align with the polarization direction of the linearly polarized optical tweezer. When its axis is not parallel or perpendicular to the optical axis of the birefringent crystal, it will experience a Casimir torque that shifts its orientation slightly. We calculate the Casimir torque and Casimir force acting on a levitated nanorod near a birefringent crystal. We also investigate the effects of thermal noise and photon recoils on the torque and force detection. We prove that a levitated nanorod in vacuum will be capable of detecting the Casimir torque under realistic conditions.Comment: 13 pages, 10 figure

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Optically anisotropic infinite cylinder above an optically anisotropic half space: Dispersion interaction of a single-walled carbon nanotube with a substrate

Cited by 9 publications

References 11 publications

Casimir-Lifshitz Torque Enhancement by Retardation and Intervening Dielectrics

Casimir-Lifshitz Torque Enhancement by Retardation and Intervening Dielectrics

Chirality-dependent properties of carbon nanotubes: electronic structure, optical dispersion properties, Hamaker coefficients and van der Waals–London dispersion interactions

Detecting Casimir torque with an optically levitated nanorod

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