Quantum critical scaling at a Bose-glass/superfluid transition: Theory and experiment for a model quantum magnet
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
22/10/2013
22/10/2013
2012
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Resumo |
In this paper we investigate the quantum phase transition from magnetic Bose Glass to magnetic Bose-Einstein condensation induced by amagnetic field in NiCl2 center dot 4SC(NH2)(2) (dichloro-tetrakis-thiourea-nickel, or DTN), doped with Br (Br-DTN) or site diluted. Quantum Monte Carlo simulations for the quantum phase transition of the model Hamiltonian for Br-DTN, as well as for site-diluted DTN, are consistent with conventional scaling at the quantum critical point and with a critical exponent z verifying the prediction z = d; moreover the correlation length exponent is found to be nu = 0.75(10), and the order parameter exponent to be beta = 0.95(10). We investigate the low-temperature thermodynamics at the quantum critical field of Br-DTN both numerically and experimentally, and extract the power-law behavior of the magnetization and of the specific heat. Our results for the exponents of the power laws, as well as previous results for the scaling of the critical temperature to magnetic ordering with the applied field, are incompatible with the conventional crossover-scaling Ansatz proposed by Fisher et al. [Phys. Rev. B 40, 546 (1989)]. However they can all be reconciled within a phenomenological Ansatz in the presence of a dangerously irrelevant operator. UEFISCDI [PN-II-ID-PCE-2011-3-1028] UEFISCDI DOE (INCITE award) DOE (INCITE award) Laboratory Directed Research and Development program at Los Alamos Laboratory Directed Research and Development program at Los Alamos [20100043DR] |
Identificador |
PHYSICAL REVIEW B, COLLEGE PK, v. 86, n. 13, pp. E716-E720, OCT 23, 2012 1098-0121 http://www.producao.usp.br/handle/BDPI/35451 10.1103/PhysRevB.86.134421 |
Idioma(s) |
eng |
Publicador |
AMER PHYSICAL SOC COLLEGE PK |
Relação |
PHYSICAL REVIEW B |
Direitos |
restrictedAccess Copyright AMER PHYSICAL SOC |
Palavras-Chave | #EINSTEIN CONDENSATION #BOSONS #LOCALIZATION #FIELD #PHYSICS, CONDENSED MATTER |
Tipo |
article original article publishedVersion |