Quantum spin liquid and electric quadrupolar states of single crystal Tb2+xTi2-xO7+y

TMU International Symposium on "New Quantum Phases Emerging from Novel Crystal Structure"

Wakita, M.^1 ; Taniguchi, T.^1 ; Edamoto, H.^1 ; Takatsu, H.^1 ; Kadowaki, H.^1

Department of Physics, Tokyo Metropolitan University, Hachioji-shi, Tokyo

192-0397, Japan^1

关键词: Dome structure;    First-order phase transitions;    Floating zone technique;    Pyrochlore oxide;    Quantum spin liquid;    Small samples;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/683/1/012023/pdf
DOI  :  10.1088/1742-6596/683/1/012023

来源: IOP

【 摘 要 】

The ground states of the frustrated pyrochlore oxide Tb2+xTi2-xO7+y, sensitively depending on the small off-stoichiometry parameter x, have been studied by specific heat measurements using well characterized samples. Single crystal Tb2+xTi2-xO7+yboules grown by the standard floating zone technique are shown to exhibit concentration (x) gradient. This off-stoichiometry parameter is determined by precisely measuring the lattice constant of small samples cut from a crystal boule. Specific heat shows that the phase boundary of the electric quadrupolar state has a dome structure in the x-T phase diagram with the highest Tc 0.5 K at about x = 0.01. This phase diagram suggests that the putative U(1) quantum spin-liquid state of Tb2+xTi2-xO7+yexists in the range x c -0.0025, which is separated from the quadrupolar state via a first-order phase-transition line x = xc.