Field evolution of magnons in α−RuCl3 by high-resolution polarized terahertz spectroscopy

  title={Field evolution of magnons in 
 by high-resolution polarized terahertz spectroscopy},
  author={Liang Wu and Arielle Little and Erik E. Aldape and Dylan Rees and Eric Thewalt and Paula Lampen-Kelley and Arnab Banerjee and Craig A. Bridges and Jiaqiang Yan and Derrick Boone and Shreyas Patankar and David Goldhaber-Golden and David G. Mandrus and Stephen E. Nagler and Ehud Altman and Joseph Orenstein},
  journal={Physical Review B},
The quantum spin liquid (QSL) -- a phase of matter with no ordered ground state -- is of fundamental interest as excitations in this phase may break the molds of bosons and fermions and develop more complicated properties. The honeycomb magnet $\ensuremath{\alpha}$-RuCl${}_{3}$ has emerged as a candidate for realization of a QSL. Although it orders at low temperature, an in-plane magnetic field of around 7 Tesla destroys the order; the nature of this transition is intensely studied. Here, the… 
Signatures of low-energy fractionalized excitations in α−RuCl3 from field-dependent microwave absorption
Topologically ordered states of matter are generically characterized by excitations with quantum number fractionalization. A prime example is the spin liquid realized in Kitaev's honeycomb-lattice
High-field quantum disordered state in α−RuCl3 : Spin flips, bound states, and multiparticle continuum
Layered $\alpha$-RuCl3 has been discussed as a proximate Kitaev spin liquid compound. Raman and THz spectroscopy of magnetic excitations confirm that the low-temperature antiferromagnetic ordered
Magnetic field-dependent low-energy magnon dynamics in α–RuCl3
Revealing the spin excitations of complex quantum magnets is key to developing a minimal model that explains the underlying magnetic correlations in the ground state. We investigate the low-energy
Identification of magnetic interactions and high-field quantum spin liquid in α-RuCl3
The microscopic spin model that quantitatively explains major observations in α-RuCl3, including the zigzag order, double-peak specific heat, magnetic anisotropy, and the characteristic M-star dynamical spin structure, is determined.
Two-step gap opening across the quantum critical point in the Kitaev honeycomb magnet α−RuCl3
A Kitaev quantum spin liquid involves fractionalized quasiparticles called itinerant Majorana fermions and localized gauge fluxes. The topological character with chiral excitations under a magnetic
The range of non-Kitaev terms and fractional particles in α-RuCl3
Significant efforts have focused on the magnetic excitations of relativistic Mott insulators, predicted to realize the Kitaev quantum spin liquid (QSL). This exactly solvable model involves a highly
Nature of Magnetic Excitations in the High-Field Phase of α-RuCl_{3}.
It is shown that the low-temperature ESR response beyond the boundary of the magnetically ordered region is dominated by single- and two-particle processes with magnons as elementary excitations.
Sub-gap optical response in the Kitaev spin-liquid candidate α-RuCl3.
  • S. Reschke, F. Mayr, +7 authors A. Loidl
  • Materials Science, Medicine
    Journal of physics. Condensed matter : an Institute of Physics journal
  • 2018
We report detailed optical experiments on the layered compound α-RuCl3 focusing on the THz and sub-gap optical response across the structural phase transition from the monoclinic high-temperature to
Dynamical and thermal magnetic properties of the Kitaev spin liquid candidate α-RuCl3
What is the correct low-energy spin Hamiltonian description of $\alpha$-RuCl$_3$? The material is a promising Kitaev spin liquid candidate, but is also known to order magnetically, the description of
Kitaev quantum spin liquid - concept and materialization
A decade ago, Alexei Kitaev proposed an exactly solvable $S$ = 1/2 model on a two-dimensional honeycomb lattice, where the spins fractionalize into Majorana fermions and form a topological quantum


Excitations in the field-induced quantum spin liquid state of α-RuCl3
The celebrated Kitaev quantum spin liquid (QSL) is the paradigmatic example of a topological magnet with emergent excitations in the form of Majorana Fermions and gauge fluxes. Upon breaking of
Field-induced magnon excitation and in-gap absorption in the Kitaev candidate RuCl3
We use time-domain terahertz spectroscopy to measure the low energy conductivity and magnons in RuCl$_3$ under external magnetic field. At zero field, an oscillation with a frequency of 0.62 THz is
Magnetic Excitations and Continuum of a Possibly Field-Induced Quantum Spin Liquid in α-RuCl_{3}.
Terahertz spectroscopy of quantum spin dynamics in α-RuCl_{3], a system proximate to the Kitaev honeycomb model, as a function of temperature and magnetic field is reported, characterizing the dynamical properties of a possibly field-induced quantum spin liquid.
Antiferromagnetic Resonance and Terahertz Continuum in α-RuCl_{3}.
Measurements of optical absorption in the zigzag antiferromagnet α-RuCl_{3} as a function of temperature T, magnetic field B, and photon energy ℏω and an upper bound on the contribution to the dc susceptibility from a magnetic excitation continuum are placed.
Probing α-RuCl_{3} Beyond Magnetic Order: Effects of Temperature and Magnetic Field.
A very rich evolution of the spin dynamics as the applied field suppresses the zigzag order and stabilizes a quantum paramagnetic state that is adiabatically connected to the fully polarized state at high fields is found.
Evidence for a Field-Induced Quantum Spin Liquid in α-RuCl_{3}.
These results provide direct evidence that α-RuCl_{3} exhibits a magnetic-field-induced QSL, and exclude that the ground state is a fully polarized ferromagnet.
Unusual Phonon Heat Transport in α-RuCl_{3}: Strong Spin-Phonon Scattering and Field-Induced Spin Gap.
The highly unusual low-temperature heat conductivity κ of α-RuCl_{3}, a prime candidate for realizing such physics, is unveiled: beyond a magnetic field of B_{c}≈7.5  T, κ increases by about one order of magnitude, both for in-plane as well as out-of-plane transport.
Kitaev exchange and field-induced quantum spin-liquid states in honeycomb α-RuCl3
The promise for spin-liquid behavior in the 4d5 honeycomb halide α-RuCl3 is discussed, and indications for a transition from zigzag order to a gapped spin liquid when applying magnetic field are found.
Gapless Spin Excitations in the Field-Induced Quantum Spin Liquid Phase of α-RuCl_{3}.
It is demonstrated that α-RuCl_{3} undergoes a quantum phase transition to a QSL in a magnetic field of 7.5 T applied in the ab plane and that this high-field QSL phase has gapless spin excitations over a field range up to 16 T.
Scattering continuum and possible fractionalized excitations in α-RuCl(3).
A Raman scattering study that provides evidence for unconventional excitations in α-RuCl_{3}, a spin-orbit coupled Mott insulator on the honeycomb lattice, and reveals unusual magnetic scattering, typified by a broad continuum.