Charge density wave transition in Na_2Ti_2Sb_2O probed by^(23)Na NMR

Herein we investigated the electronic properties of layered transition-metal oxides NazTi2Sb2O by 23Na nuclear magnetic reso- nance （NMR） measurement. The resistivity, susceptibility and specific heat measurements show a phase transition at approxi- mately 114 K （TA）. No splitting or broadening in the central line of 23Na NMR spectra is observed below and above the transi- tion temperature indicating no internal field being detected. The spin-lattice relaxation rate divided by T （I/T1T） shows a sharp drop at about 110 K which suggests a gap opening behavior. Below the phase transition temperature zone, I/T1T shows Fermi liquid behavior but with much smaller value indicating the loss of large part of electronic density of states （DOS） because of the gap. No signature of the enhancement of spin fluctuations or magnetic order is found with the decreasing temperature. These results suggest a commensurate charge-density-wave （CDW） phase transition occurring.

Herein we investigated the electronic properties of layered transition-metal oxides Na2Ti2Sb2O by23Na nuclear magnetic resonance(NMR)measurement.The resistivity,susceptibility and specific heat measurements show a phase transition at approximately 114 K(TA).No splitting or broadening in the central line of23Na NMR spectra is observed below and above the transition temperature indicating no internal field being detected.The spin-lattice relaxation rate divided by T(1/T1T)shows a sharp drop at about 110 K which suggests a gap opening behavior.Below the phase transition temperature zone,1/T1T shows Fermi liquid behavior but with much smaller value indicating the loss of large part of electronic density of states(DOS)because of the gap.No signature of the enhancement of spin fluctuations or magnetic order is found with the decreasing temperature.These results suggest a commensurate charge-density-wave(CDW)phase transition occurring.