Soliton spin excitations in an anisotropic Heisenberg ferromagnet with octupole-dipole interaction

Daniel, M.; Kavitha, L.; Rajamani, Amuda

doi:10.1103/physrevb.59.13774

Cited by 131 publications

(55 citation statements)

References 32 publications

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“…One half spin corresponds to the two possible positions of the proton in the double-well potential along the O-O bond (hydrogen bond). This potential is a consequence of the interaction [46][47][48] for the spin operators in terms of the bosonic operators a † n , a n , which satisfy the usual Bose commutation relations. At a sufficiently low-temperature limit, the ground-state expectation value of a † n a n is small compared to 2S and n, therefore we can use the semi-classical expansions as where ε = 1/ √ S and, using (2), dimension-less Hamiltonian (1) can be written in a power series of ε, as Hamiltonian (3) characterizes the low-energy non-linear property of hydrogen-bonded chains in an oblique electric field.…”

Section: Mathematical Background Of Proton Dynamicsmentioning

confidence: 99%

Nano breathers and molecular dynamics simulations in hydrogen-bonded chains

Kavitha¹,

Muniyappan²,

Prabhu³

et al. 2012

J Biol Phys

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Non-linear localization phenomena in biological lattices have attracted a steadily growing interest and their existence has been predicted in a wide range of physical settings. We investigate the non-linear proton dynamics of a hydrogen-bonded chain in a semiclassical limit using the coherent state method combined with a Holstein-Primakoff bosonic representation. We demonstrate that even a weak inherent discreteness in the hydrogenbonded (HB) chain may drastically modify the dynamics of the non-linear system, leading to instabilities that have no analog in the continuum limit. We suggest a possible localization mechanism of polarization oscillations of protons in a hydrogen-bonded chain through modulational instability analysis. This mechanism arises due to the neighboring protonproton interaction and coherent tunneling of protons along hydrogen bonds and/or around heavy atoms. We present a detailed analysis of modulational instability, and highlight the role of the interaction strength of neighboring protons in the process of bioenergy localization. We perform molecular dynamics simulations and demonstrate the existence of nanoscale discrete breather (DB) modes in the hydrogen-bonded chain. These highly

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Section: Mathematical Background Of Proton Dynamicsmentioning

confidence: 99%

Nano breathers and molecular dynamics simulations in hydrogen-bonded chains

Kavitha¹,

Muniyappan²,

Prabhu³

et al. 2012

J Biol Phys

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“…In the low temperature long wavelength limit, it is appropriate to make continuum approximation [14] by replacing u j (t) by u(x, t) and by expanding…”

Section: Original Papermentioning

confidence: 99%

Nonlinear excitations in self‐assembled one‐dimensional quantum dot arrays

Rajamani¹,

Ramya²

2005

Physica Status Solidi (b)

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Self-assembled quantum dot arrays are modeled by one-dimensional Heisenberg ferromagnetic spin chains. The interdot interaction is responsible for the ferromagnetic ordering. Starting from the Heisenberg Hamiltonian, using Bosonic operators coupled with Glauber's coherent state ansatz, the equation of motion is derived. In the lower order of the expansion parameters the dynamics is found to be governed by the nonlinear Schrödinger equation which admits soliton solution.

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“…Recently, it is found that the two coupled spin ladder is expected to be integrable only when the two ferromagnetic legs are locked together at least at the level of the leading order allowing only small freedom for the individual spins [10,11]. Also, switching of magnetization via soliton flipping has been demonstrated in a biquadratic ferromagnet with varying exchange interactions [12][13][14][15][16][17]. High density data storage devices making use of ferromagnetic spin chains are indispensable for the growth of present day technology.…”

Section: Introductionmentioning

confidence: 98%