Field-induced quantum spin disordered state in spin-1/2 honeycomb magnet Na2Co2TeO6

Abstract

Spin-orbit coupled honeycomb magnets with the Kitaev interaction have received a lot of attention due to their potential of hosting exotic quantum states including quantum spin liquids. Thus far, the most studied Kitaev systems are 4d/5d-based honeycomb magnets. Recent theoretical studies predicted that 3d-based honeycomb magnets, including Na2Co2TeO6 (NCTO), could also be a potential Kitaev system. Here, we have used a combination of heat capacity, magnetization, electron spin resonance measurements alongside inelastic neutron scattering (INS) to study NCTO’s quantum magnetism, and we have found a field-induced spin disordered state in an applied magnetic field range of 7.5 T < B (⊥ b-axis) < 10.5 T. The INS spectra were also simulated to tentatively extract the exchange interactions. As a 3d-magnet with a field-induced disordered state on an effective spin-1/2 honeycomb lattice, NCTO expands the Kitaev model to 3d compounds, promoting further interests on the spin-orbital effect in quantum magnets.

Intermediate Quantum Spin Liquid Phase in the Kitaev Material $α$-RuCl$_3$ under High Magnetic Fields up to 100 T

“…Such a magnetic disordered phase is separated from the trivial polarized state by a quantum phase transition, suggesting the existence of the longsought QSL phase as predicted in previous model studies. Our work opens the avenue for the exploration of the QSL phase in the Kitaev materials under high out-of-plane fields up to 100-T class, which is not limited to α-RuCl 3 but may also apply for other Kitaev materials like Na 2 Co 2 TeO 6 [56,57], etc. Moreover, further experimental characteristics of the intermediate QSL phase can be started from here.…”

Magnetic excitations of the field induced states in BaCo2(AsO4)2 probed by time-domain terahertz spectroscopy

“…Recently, the 3d 7 Co-based honeycomb materials with high spin state S=3/2 and effective orbital angular momentum L=1 have been proposed as new candidates of Kitaev QSLs and have attracted wide attention [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. In transition metal 4d-and 5d-electron systems, the spatially extended d-electron wave function leads to nonnegligible longer range coupling, which is detrimental to Kitaev QSL.…”

Excitations in the ordered and paramagnetic states of honeycomb magnet Na2Co2TeO6

“…Furthering the Jackeli-Khaliullin mechanism, recent theoretical studies indicate that Kitaev interactions can arise between 3d transition-metal ions with a high-spin d 7 electronic configuration (t [31,[35][36][37][38], Co-TiO 3 [39,40], BaCo 2 (AsO 4 ) 2 [41,42] and BaCo 2 (PO 4 ) 2 [43]. Although all of them develop long-range order at low temperatures, the ordering can be suppressed by inplane fields in Na 2 Co 2 TeO 6 [44,45] and BaCo 2 (AsO 4 ) 2 [42], similar to the behavior of α-RuCl 3 . Their thermal transport properties are also similar to α-RuCl 3 [42,46].…”

“…Their thermal transport properties are also similar to α-RuCl 3 [42,46]. With the promising properties, Na 2 Co 2 TeO 6 has recently been intensively studied [44,45,[47][48][49][50][51]. A widely recognized goal is to establish the magnetic interaction model with inelastic neutron scattering (INS) [45,47,[49][50][51], yet most of the experiments so far were performed on powder samples and pointed to diversifying sets of parameters.…”