Evidence of a field-induced Berezinskii–Kosterlitz–Thouless scenario in a two-dimensional spin–dimer system

Tutsch, Ulrich; Wolf, B.; Weßel, Stefan; Postulka, L.; Tsui, Y. K.; Jeschke, Harald O.; Opahle, Ingo; Saha-Dasgupta, T.; Valentí, Roser; Brühl, A.; Remović-Langer, Katarina; Kretz, Tonia; Lerner, Hans‐Wolfram; Wagner, Mat­thias; Lang, Michael

doi:10.1038/ncomms6169

Cited by 49 publications

(40 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, in 2D systems, long-range ordering is suppressed by large quantum and thermal fluctuations, and topological ordering such as the Berezinskii-Kosterlitz-Thouless (BKT) transition [28][29][30] and unusual quantum critical behavior are expected to occur. Recently, the BKT transition has been reported for the 2D DQM C 36 H 48 Cu 2 F 6 N 8 O 12 S 2 [31]. However, the understanding of 2D systems of interacting triplons is insufficient.…”

Section: Introductionmentioning

confidence: 99%

Quasi-two-dimensional Bose-Einstein condensation of spin triplets in the dimerized quantum magnetBa2CuSi2O6Cl2

et al. 2016

View full text Add to dashboard Cite

We synthesized single crystals of composition Ba2CuSi2O6Cl2 and investigated its quantum magnetic properties. The crystal structure is closely related to that of the quasi-two-dimensional (2D) dimerized magnet BaCuSi2O6 also known as Han purple. Ba2CuSi2O6Cl2 has a singlet ground state with an excitation gap of ∆/kB = 20.8 K. The magnetization curves for two different field directions almost perfectly coincide when normalized by the g-factor except for a small jump anomaly for a magnetic field perpendicular to the c axis. The magnetization curve with a nonlinear slope above the critical field is in excellent agreement with exact-diagonalization calculations based on a 2D coupled spin-dimer model. Individual exchange constants are also evaluated using density functional theory (DFT). The DFT results demonstrate a 2D exchange network and weak frustration between interdimer exchange interactions, supported by weak spin-lattice coupling implied from our magnetostriction data. The magnetic-field-induced spin ordering in Ba2CuSi2O6Cl2 is described as the quasi-2D Bose-Einstein condensation of triplets.

show abstract

Section: Introductionmentioning

confidence: 99%

Quasi-two-dimensional Bose-Einstein condensation of spin triplets in the dimerized quantum magnetBa2CuSi2O6Cl2

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The exchange couplings we obtained by performing total energy calculations with the GGA and GGA+U functionals and mapping the energy difference of various spin configurations onto a Heisenberg model as described in Refs. 43,44. For the inter-plane exchange coupling, we used a 1x1x2 supercell.…”

Section: Experimental and Calculation Detailsmentioning

confidence: 99%

Zigzag antiferromagnetic quantum ground state in monoclinic honeycomb lattice antimonatesA3Ni2SbO6(A=<

et al. 2015

Self Cite

View full text Add to dashboard Cite

We present a comprehensive experimental and theoretical study of the electronic and magnetic properties of two quasi-two-dimensional (2D) honeycomb-lattice monoclinic compounds A 3 Ni 2 SbO 6 (A=Li, Na). Magnetic susceptibility and specific heat data are consistent with the onset of antiferromagnetic (AFM) long range order at low temperatures with Néel temperatures ~ 14 and 16 K for Li 3 Ni 2 SbO 6 and Na 3 Ni 2 SbO 6 , respectively. The effective magnetic moments of 4.3  B /f.u. (Li 3 Ni 2 SbO 6 ) and 4.4  B /f.u. (Na 3 Ni 2 SbO 6 ) indicate that Ni 2+ is in a high-spin configuration (S=1). The temperature dependence of the inverse magnetic susceptibility follows the Curie-Weiss law in the high-temperature region and shows positive values of the Weiss temperature ~ 8 K (Li 3 Ni 2 SbO 6 ) and ~12 K (Na 3 Ni 2 SbO 6 ) pointing to the presence of nonnegligible ferromagnetic interactions, although the system orders AFM at low temperatures. In addition, the magnetization curves reveal a field-induced (spin-flop type) transition below T N that can be related to the magnetocrystalline anisotropy in these systems. These observations are in agreement with density functional theory calculations, which show that both antiferromagnetic and ferromagnetic intralayer spin exchange couplings between Ni 2+ ions are present in the honeycomb planes supporting a zigzag antiferromagnetic ground state. Based on our experimental measurements and theoretical calculations we propose magnetic phase diagrams for the two compounds. 75.30.Kz; 75.10.Dg; 75.30.Gw; 75.30.Et

show abstract

“…Note that the isoelectronic substitution of 10% Sr 2+ for Ba 2+ is reflected in the calculation only by the experimentally determined lattice constants and interatomic distances but not by actual replacement of Ba sites in a supercell approach. The 21 energies can be fitted [30] against five Heisenberg exchange couplings J i with very Table 1. A GGA+U functional with U = 8 eV and JH = 1 eV is used.…”

Section: Electronic Structure Calculationsmentioning

confidence: 99%

Stabilization of the tetragonal structure in(Ba1−xSrx)CuSi2O6

et al. 2016

View full text Add to dashboard Cite

We present a structural analysis of the substituted system (Ba1−xSrx)CuSi2O6, which reveals a stable tetragonal crystal structure down to 1.5 K. We explore the structural details with lowtemperature neutron and synchrotron powder diffraction, room-temperature and cryogenic highresolution NMR, as well as magnetic-and specific-heat measurements and verify that a structural phase transition into the orthorhombic structure which occurs in the parent compound BaCuSi2O6, is absent for the x = 0.1 sample. Furthermore, synchrotron powder-diffraction patterns show a reduction of the unit cell for x = 0.1 and magnetic measurements prove that the Cu-dimers are preserved, yet with a slightly reduced intradimer coupling Jintra. Pulse-field magnetization measurements reveal the emergence of a field-induced ordered state, tantamount to Bose-Einsteincondensation (BEC) of triplons, within the tetragonal crystal structure of I 41/acd. This material offers the opportunity to study the critical properties of triplon condensation in a simple crystal structure.

show abstract

Evidence of a field-induced Berezinskii–Kosterlitz–Thouless scenario in a two-dimensional spin–dimer system

Cited by 49 publications

References 56 publications

Quasi-two-dimensional Bose-Einstein condensation of spin triplets in the dimerized quantum magnetBa2CuSi2O6Cl2

Quasi-two-dimensional Bose-Einstein condensation of spin triplets in the dimerized quantum magnetBa2CuSi2O6Cl2

Zigzag antiferromagnetic quantum ground state in monoclinic honeycomb lattice antimonatesA3Ni2SbO6(A=<

Stabilization of the tetragonal structure in(Ba1−xSrx)CuSi2O6

Contact Info

Product

Resources

About