Bose-Einstein condensation of triplons in the S=1 tetramer antiferromagnet K2Ni2(MoO4)3: A compound close to quantum critical point

Abstract

The structure of K2Ni2(MoO4)3 consists of S=1 tetramers formed by Ni^{2+} ions. The magnetic susceptibility chi(T) and specific heat Cp(T) data on a single crystal show a broad maximum due to the low-dimensionality of the system with short-range spin correlations. A sharp peak is seen in chi(T) and Cp(T) at about 1.13 K, well below the broad maximum. This is an indication of magnetic long-range order i.e., the absence of spin-gap in the ground state. Interestingly, the application of a small magnetic field (H>0.1 T) induces magnetic behavior akin to Bose-Einstein condensation (BEC) of triplon excitations observed in some spin-gap materials. Our results demonstrate that the temperature-field (T-H) phase boundary follows a power-law (T-T_{N})propotional to H^(1/alpha) with the exponent 1/alpha close to 2/3, as predicted for BEC scenario. The observation of BEC of triplon excitations in small H infers that K2Ni2(MoO4)3 is located in the proximity of a quantum critical point, which separates the magnetically ordered and spin-gap regions of the phase diagram.

arXiv comment5 pages, 5 figures, Accepted in Phys. Rev. B Rapid Communications

References in corpus (20)

• Bose-Einstein Condensation in Magnetic Insulators
• Realization of Bose-Einstein condensation of dilute magnons in TlCuCl${}_3$
• Thermodynamics of Spin S = 1/2 Antiferromagnetic Uniform and Alternating-Exchange Heisenberg Chains
• Quantum Criticality: competing ground states in low dimensions
• Exact dimer ground state of the two dimensional Heisenberg spin system SrCu_2(BO_3)_2
• Coupled Ladders in a Magnetic Field
• Magnetic Superstructure in the Two-Dimensional Quantum Antiferromagnet SrCu2(BO3)2
• Magnetic Field-Induced Condensation of Triplons in Han Purple Pigment BaCuSi${}_2$O${}_6$
• Bose-Einstein Condensation of Magnons in Cs2CuCl4
• Quantum and classical criticality in a dimerized quantum antiferromagnet
• Successive magnetic phase transitions and multiferroicity in Spin-1 triangular lattice antiferromagnet Ba${}_3$NiNb${}_2$O${}_9$
• Field-induced Bose-Einstein Condensation of triplons up to 8 K in Sr3Cr2O8
• Characteristic BEC scaling close to Quantum Critical Point in BaCuSi2O6
• Universal scaling at field-induced magnetic phase transitions
• Bose-Einstein Condensation of Triplons in Ba3Cr2O8
• Singlet ground state in the spin-1/2 dimer compound Sr3Cr2O8
• Spin-gap behaviour in the 2-leg spin-ladder BiCu2PO6
• Asymmetric quintuplet condensation in the frustrated S=1 spin dimer compound Ba3Mn2O8
• Singlet Ground State and Magnetization Plateaus in Ba${}_3$Mn${}_2$O${}_8$
• Observation of S = 1/2 quasi-one-dimensional magnetic and magneto-dielectric behavior in a cubic SrCuTe2O6

Cited by in corpus (2)

• Electronic structure and magnetic properties of 3d-4f double perovskite material
• The $S=1$ dimer system K${}_2$Ni(MoO${}_4$)${}_2$: a candidate for magnon Bose-Einstein condensation