Magnetic field effects on the quantum spin liquid behaviors of NaYbS$_2$

Abstract

Spin-orbit coupling is an important ingredient in many spin liquid candidate materials, especially among the rare-earth magnets and Kitaev materials. We explore the rare-earth chalcogenides NaYbS2 where the Yb 3+ ions form a perfect triangular lattice. Unlike its isostructural counterpart YbMgGaO4 and the kagomé lattice herbertsmithite, this material does not have any site disorders both in magnetic and non-magnetic sites. We carried out the thermodynamic and inelastic neutron scattering measurements. The magnetic dynamics could be observed with a broad gapless excitation band up to 1.0 meV at 50 mK and 0 T, no static long-range magnetic ordering is detected down to 50 mK. We discuss the possibility of Dirac spin liquid for NaYbS2. We identify the experimental signatures of field-induced transitions from the disordered spin liquid to an ordered antiferromagnet with an excitation gap at finite magnetic fields and discuss this result with our Monte Carlo calculation of the proposed spin model. Our findings could inspire further interests in the spin-orbit-coupled spin liquids and the magnetic ordering transition from them.

Synthesis and Anisotropic Magnetism in Quantum Spin Liquid Candidates $A$YbSe$_2$ ($A$ = K and Rb)

“…This could be re-lated to the intralayer and interlayer distance of magnetic Yb 3+ ions. Based on this assumption, we obtain each highest transition temperature T m with the corresponding field H m in NaYbS 2 and Na/K/Rb/CsYbSe 2 series, 49,50,52 and plotted them against the inversed intralayer distance (1/d intra ) of Yb 3+ and interlayer distance (1/d inter ), as shown in Fig. 7(e-f).…”

“…[41][42][43][44][45][46][47] Further, no long-range order has been observed in heat capacity at zero field down to mK temperatures at low magnetic fields. 33,[48][49][50][51][52][53][54][55][56] Quantum disordered or QSL ground state is proposed in NaYbO 2 48,51,57 and the signature of the magnetic excitation continuum has been found in NaYbSe 2 from 0.1 to 2.5 meV in inelastic neutron scattering (INS) measurement, suggesting the ground state of NaYbSe 2 is a QSL with a spinon Fermi surface. 58 The continuum-like excitation with shortrange order has been found in CsYbSe 2 , indicating it may be located close to the critical boundary between QSL and 120 • phase.…”

Quantum spin state transitions in spin-1 equilateral triangular lattice antiferromagnet Na$_2$BaNi(PO$_4$)$_2$

“…One celebrated example is the quantum spin liquid (QSL) [1][2][3][4] that can host non-abelian quasiparticle [5] and fractional excitations [6,7] known as spinons [8,9], which allows quantum mechanical encryption and transportation of information with potential for creating a qubit that is protected against environmental influences [10]. For example, the recently studied NaYbO 2 [11], NaYbS 2 [12][13][14], NaYbSe 2 [15][16][17], CsYbSe 2 [18,19], and YbMgGaO 4 [20][21][22][23][24][25][26][27][28] are ETLAFs with effective spin-1/2 for Yb 3+ ions, and have been proposed as QSL candidates. Due to the Mg/Ga site disorder, the ground state of YbMgGaO 4 [29][30][31][32][33] also has been proposed as spin glass or random spin singlet state.…”

Low-energy Spin Dynamics of Quantum Spin Liquid Candidate $NaYbSe_{2}$

“…It may mean that the spin system enters a paramagnetic state or transition state in the magnetic field region. A larger magnetic field (> 3 T) induces magnetically ordered phases, which have been observed and studied in NaYbO 2 [3] and NaYbS 2 [33].…”