相关论文: ESR studies on the spin-liquid candidate $\kappa$-…
We study the ultralow-temperature thermodynamics and thermal conductivity ($\kappa$) of the single-crystal rare-earth chalcogenides NaYbS$_2$ and NaYbSe$_2$, which have an ideal triangular lattice of the Yb$^{3+}$ ions and have been…
The spin excitations from the nonmagnetic charge-ordered insulating state of $\alpha$-(BEDT-TTF)$_2$I$_3$ at ambient pressure have been investigated by probing the static and low-frequency dynamic spin susceptibilities via site-selective…
The two-dimensional Hubbard model on the anisotropic triangular lattice, with two different hopping amplitudes $t$ and $t^\prime$, is relevant to describe the low-energy physics of $\kappa$-(ET)$_2$X, a family of organic salts. The…
Quantum spin liquids (QSLs) are fluid-like states of quantum spins where its long-range ordered state is destroyed by quantum fluctuations. The ground state of QSL and its exotic phenomena, which have been extensively discussed for decades,…
Proton NMR measurements on the organic superconductor $\kappa-(ET)_2Cu[N(CN)_2]Br$ ($T_C = 11.6$ K) exhibit stretched exponential spin-lattice relaxation below $T\approx 25$ K, suggestive of an inhomogeneous magnetic phase that develops in…
We present high-resolution measurements of the relative length change as a function of temperature of the organic charge-transfer salt $\kappa$-(BEDT-TTF)$_2$Hg(SCN)$_2$Cl. We identify anomalous features at $T_g \approx\,63$ K which can be…
A muon-spin relaxation (muSR) investigation is presented for the molecular superconductor kappa-(BEDT-TTF)2Cu[N(CN)2Br]. Evidence is found for low-temperature phase-separation, with only a fraction of the sample showing a superconducting…
The vortex state in a single crystal of the layered organic superconductor \kappa-(BEDT-TTF2Cu(NCS)2, where BEDT-TTF (or ET) is bis(ethylenedithio)tetrathiafulvalene, was studied by 1H-NMR. Under a low field region around 0.75 T, the vortex…
The spin relaxation in chromium spinel oxides $A$Cr$_{2}$O$_{4}$ ($A=$ Mg, Zn, Cd) is investigated in the paramagnetic regime by electron spin resonance (ESR). The temperature dependence of the ESR linewidth indicates an unconventional…
The Mott insulator \kappa-(BEDT-TTF)2Cu[N(CN)2]Cl consists of molecular dimers arranged on an anisotropic triangular lattice and develops a canted antiferromagnetic ground state. It has recently been suggested that this system features…
Cs2CoBr4 is a triangular-lattice antiferromagnet which can be viewed as weakly interacting spin chains due to spatially anisotropic frustrating exchange couplings. The spin-orbit interaction in Co(2+) spin-3/2 ions leads to a strong…
Kitaev iridates have been proposed as candidates for realizing an elusive quantum spin liquid (QSL) state, in which strong spin-orbit coupling and bond-directional exchange generate a highly frustrated and entangled ground state. However,…
Spin fluctuation-induced superconductivity in quasi-two dimensional organic compounds, \kappa-BEDT-TTF salts, is investigated within a fluctuation exchange (FLEX) approximation using a half-filled Hubbard model with a right-angled isosceles…
We discuss universal features on the electron spin resonance (ESR) of a temperature-induced Tomonaga-Luttinger liquid phase in a wide class of weakly coupled $S=1/2$ antiferromagnetic spin chains such as spin ladders, spin tubes and…
We report thermodynamic measurements of the S=1/2 kagome lattice antiferromagnet ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$, a promising candidate system with a spin-liquid ground state. Using single crystal samples, the magnetic susceptibility both…
We have measured the temperature dependences of the thermal conductivity of Ba$_2$Cu$_{3-x}M_x$O$_4$Cl$_2$ ($M$ = Pd, Ni, Co; $x$ = 0, 0.03) single crystals including two-dimensional (2D) Cu$_3$O$_4$ planes consisting of a strong 2D spin…
The effects of pressure on a quantum spin liquid are investigated in an organic Mott insulator $\kappa$-(ET)$_2$Ag$_2$(CN)$_3$ with a spin-1/2 triangular lattice. The application of negative chemical pressure to…
Cu(C$_8$H$_6$N$_2$)Cl$_2$, a strong-rung spin-1/2 Heisenberg ladder compound, is probed by means of electron spin resonance (ESR) spectroscopy in the field-induced gapless phase above $H_{c1}$. The temperature dependence of the ESR…
The layered organic compounds, kappa-(BEDT-TTF)_2Cu[N(CN)_2X (X=Cl, Br) are metals at ambient temperatures. At low temperatures, the Cl compound is a weakly ferromagnetic Mott insulator while the isostructural Br compound is a…
We have measured and analyzed the dielectric constant of the dimer Mott insulator $\kappa-$(BEDT-TTF)$_2$Cu$_2$(CN)$_3$, which is known as a playground for a spin-liquid state. Most unexpectedly, this particular organic salt has nontrivial…