Analytical and numerical studies of disordered spin-1 Heisenberg chains with aperiodic couplings

Autor(es)

Casa Grande, H. L. ^{[1, 2]} ; Laflorencie, N. ^[2] ; Alet, F. ^[2] ; Vieira, A. P. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Fis, BR-05314970 Sao Paulo - Brazil

^[2] Univ Toulouse, CNRS, IRSAMC, Phys Theor Lab, F-31062 Toulouse - France

• Tipo de documento: Artigo Científico
• Fonte: Physical Review B; v. 89, n. 13 APR 14 2014.
• Citações Web of Science: 6

Resumo

We investigate the low-temperature properties of the one-dimensional spin-1 Heisenberg model with geometric fluctuations induced by aperiodic but deterministic coupling distributions, involving two parameters. We focus on two aperiodic sequences, the Fibonacci sequence and the 6-3 sequence. Our goal is to understand how these geometric fluctuations modify the physics of the (gapped) Haldane phase, which corresponds to the ground state of the uniform spin-1 chain. We make use of different adaptations of the strong-disorder renormalization-group (SDRG) scheme of Ma, Dasgupta, and Hu, widely employed in the study of random spin chains, supplemented by quantum Monte Carlo and density-matrix renormalization-group numerical calculations, to study the nature of the ground state as the coupling modulation is increased. We find no phase transition for the Fibonacci chain, while we show that the 6-3 chain exhibits a phase transition to a gapless, aperiodicity-dominated phase similar to the one found for the aperiodic spin-1/2 XXZ chain. Contrary to what is verified for random spin-1 chains, we show that different adaptations of the SDRG scheme may lead to different qualitative conclusions about the nature of the ground state in the presence of aperiodic coupling modulations. (AU)

• Processo FAPESP: 09/08171-3 - Propriedades termodinâmicas de modelos de dímeros e de cadeias aperiódicas de spins quânticos
• Beneficiário: Helder Luciani Casa Grande
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 12/02287-2 - Simulações de Monte Carlo Quântico para cadeias de Heisenberg de spin-1 com desordem
• Beneficiário: Helder Luciani Casa Grande
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado