Ultrasonic investigation of the transition at 6 K in the spin-liquid candidate kappa-(BEDT-TTF)(2)Cu-2(CN)(3)

作者：Poirier Mario^*; de Lafontaine Mathieu; Miyagawa Kazuya; Kanoda Kazushi; Shimizu Yasuhiro

来源：Physical Review B, 2014, 89(4): 045138.

DOI：10.1103/PhysRevB.89.045138

An ultrasonic measurement has been performed on the spin-liquid organic candidate kappa-(BEDT-TTF)(2)Cu-2(CN)(3) at low temperatures. A softening anomaly was observed on the longitudinal velocity along a direction perpendicular to the organic planes with a consistent one on the attenuation. The velocity anomaly appears as a frequency dependent softening peak below 20 K with a maximum value found near 5-6 K. A magnetic field affects predominantly the peak only below a temperature T-p = 5.9 K that is associated with the 6 K transition found on other physical properties. We suggest to relate the frequency dependent velocity softening at low temperatures to a spinon-phonon coupling, softening that is reduced below 5.9 K due to a pairing instability transition of the spinons.

• 出版日期2014-1-29