Field-Induced Magnonic Liquid in the 3D Spin-Dimerized AntiferromagnetSr3Cr2O8

Abstract

We report on spectroscopy study of elementary magnetic excitations in an Ising-like antiferromagnetic chain compound SrCo2V2O8 as a function of temperature and applied transverse magnetic field up to 25 T. An optical as well as an acoustic branch of confined spinons, the elementary excitations at zero field, are identified in the antiferromagnetic phase below the Néel temperature of 5 K and described by a one-dimensional Schrödinger equation. The confinement can be suppressed by an applied transverse field and a quantum disordered phase is induced at 7 T. In this disordered paramagnetic phase, we observe three emergent fermionic excitations with different transverse-field dependencies. The nature of these modes is clarified by studying spin dynamic structure factor of a 1D transverse-field Heisenberg-Ising (XXZ) model using the method of infinite time evolving block decimation. Our work reveals emergent quantum phenomena and provides a concrete system for testifying theoretical predications of one-dimension quantum spin models.

Adiabatic physics of an exchange-coupled spin-dimer system: Magnetocaloric effect, zero-point fluctuations, and possible two-dimensional universal behavior

“…With this insight, our results imply that a naive acceptance of the apparent sample temperature in pulsed-field measurements may lead to the results on BEC systems being interpreted erroneously 13,14 . We demonstrate this by exploiting the low-field QCPs of an organic spin-dimer network, Cu(pyz)(gly)ClO 4 (pyz = pyrazine; gly = glycinate) 15 , to measure both pulsed-field and quasistatic magnetometry across the full phase diagram of the material.…”

How many spin liquids are there in Ca$_{10}$Cr$_7$O$_{28}$?

“…The first surprise in Ca 10 Cr 7 O 28 is a chemical one; the highly-unusual, spin-1/2, Cr 5+ valence state [15]. Structurally, Ca 10 Cr 7 O 28 has much in common with the quantum dimer system SrCr 2 O 8 [20,21]. However the inclusion of non-magnetic Cr 6+ ions converts the triangular lattice of SrCr 2 O 8 into a bilayers of a "breathing" Kagome lattice [19] -cf.…”

Theory of Ca$_{10}$Cr$_7$O$_{28}$ as a bilayer breathing-kagome magnet: Classical thermodynamics and semi-classical dynamics

“…Structurally, Ca 10 Cr 7 O 28 has much in common with SrCr 2 O 8 , a Mott insulator based on Cr 5+ ions, which has been studied for its quantum dimer ground state [43]. SrCr 2 O 8 is composed of stacked, triangular-lattice bilayers, and has the high-temperature space group R3m, [44].…”

“…At T = 275 K, it undergoes a structural phase transition into a phase with space group C2/c, lifting the orbital degeneracy of the Cr 5+ ions [45]. This promotes a low-temperature phase in which Cr 5+ form a triangular lattice of singlet dimers, each arranged along the c-axis connecting the two planes of each bilayer [43,45,46]. Ca 10 Cr 7 O 28 differs from SrCr 2 O 8 through the inclusion of non-magnetic Cr 6+ ions, at a ratio of 6 Cr 5+ ions to 1 Cr 6+ [24].…”

“…At low fields, the magnetisation is found to be nearly linear in B, with an associated susceptibility χ 0 = 3.0 emu/mol Oe , at T = 1.8 K; a large value even by comparison with heavy Fermion materials [Table I]. This behaviour stands in marked contrast with SrCr 2 O 8 , where the energy gap from the dimerized ground-state to the lowest-lying triplet excitation ensures that the magnetisation remains zero up to a field H c1 = 30.4 T [43,46]. The magnetization of Ca 10 Cr 7 O 28 is also broadly independent of the direction in which field is applied, and saturates at a relatively low field, with a sharp kink in M (H) observed at a scale of H ∼ 1 T, and complete saturation is observed for fields no greater than H ∼ 10 T, at a temperature of 1.8 K [21,22].…”