Breathers and Raman scattering in a two-leg ladder with staggered Dzyaloshinskii-Moriya interaction

Abstract

Recent experiments have revealed the role of the staggered Dzyaloshinskii-Moriya interaction in the magnetized phase of an antiferromagnetic spin-1 / 2 two-leg ladder compound under a uniform magnetic field. We derive a low-energy effective field theory describing a magnetized two-leg ladder with a weak staggered Dzyaloshinskii-Moriya interaction. This theory predicts the persistence of the spin gap in the magnetized phase, in contrast to standard two-leg ladders, and the presence of bound states in the excitation spectrum. Such bound states are observable in Raman scattering measurements. These results are then extended to intermediate Dzyaloshinskii-Moriya interaction using exact diagonalizations.

Modulation of breathers in cigar-shaped Bose–Einstein condensates

“…We can make the breather to move with the choice of b such that b = − tan(t)/16(tan 2 (t) + 2) + 3 √ 2 arctan(tan(t)/ √ 2)/32, to get f 2 = 0; also, the choice c t = −b 2 t /2a 2 makes f 3 = 0. In this way, using the same nonlinearity above the potential is also the same shown in (13). But now the breather present a nontrivial phase in (9), and it presents an interesting behavior: it seems to split in two parts in the time coordinate.…”

“…They have been originally introduced in the sine-Gordon equation [1], but they can also be found in other scenarios, controlled by the modified Korteweg-de Vries equation [2], the Davey-Stewartson [3] and the nonlinear Schrödinger equation [4]. In various physical systems, which are well described by nonlinear equations, breathers directly affect their electronic, magnetic, optical, vibrational and transport properties, such as in Josephson superconducting junctions [5,6], charge density wave systems [7], 4-methyl-pyridine crystals [8], metallic nanoparticles [9], conjugated polymers [10], micromechanical oscillator arrays [11], antiferromagnetic Heisenberg chains [12,13], and semiconductor quantum wells [14].…”

Thermodynamic properties of quantum sine-Gordon spin chain system KCuGaF6

“…(1): Yb 4 As 3 , 23-25 PM·Cu(NO 3 ) 2 ·(H 2 O) 2 (PM, pyrimidine) [26][27][28][29][30] and CuCl 2 ·2[(CD 3 ) 2 SO]. [31][32][33] Because the elementary excitations and thermodynamic properties of quantum SG systems have been of great interest, numerous theoretical investigations have been published, [34][35][36][37][38][39][40][41][42][43][44][45] and the theoretical results have been used to analyze experimental results on the above-mentioned substances. Moreover, new experiments have been proposed on the basis of theoretical results.…”

Anisotropy of magnetic interactions in the spin-ladder compound(C5H12N)2CuBrČižmár1, Ozerov2, Wosnitza3 et al. 2010Phys. Rev. B355420View full textAdd to dashboardCite

“…Theoretical and experimental studies of the anisotropy effects in spin ladders (and other quantum magnets) appear to be important topics in quantum magnetism because the anisotropy can significantly modify the ground-state properties and low-energy excitation spectrum of those systems [13][14][15][16][17][18][19] . Piperidinium copper bromide, (C 5 H 12 N) 2 CuBr 4 [abbreviated as BPCB or (Hpip) 2 CuBr 4 ], is known as a prototypical realization of the two-leg spin-1 2 antiferromagnetic ladder system in the strong-coupling limit (J ⊥ > J ) 7 with an optimal energy scale for experimental investigations.…”

“…The observation of finite biaxial anisotropy (which breaks the U(1) rotational symmetry) can be of particular importance when applying the magnon BEC formalism for the description of the field-induced antiferromagnetically ordered phase in BPCB at lower temperatures 8,9 . Fi- nally, understanding the role of anisotropy and its experimental consequences in spin ladders itself is of fundamental interest [13][14][15][16][17][18][19] . Therefore, our findings have a broader impact, offering BPCB as a model system for investigating also anisotropy effects in spin ladders.…”