Fig. 1. The chemical structure of Pd(dmit)2 and EtxMe4−xSb+. The size of cation is becomes larger with increasing x. Three types of electronic ground states are obtained by each cation.
A kind of anion radical salt EtMe3Sb[Pd(dmit)2]2 is one of the best candidate compounds for study of quantum spin liquid state, which is a kind of macroscopic appearance of quantum phenomena. Since an electronic structure of X[Pd(dmit)2]2 can be controlled by the tuning of size of cation X, the possibility of chemical pressure effect by deuteration of cation EtMe3Sb. We have performed specific heat measurement for Full deuterated compound of (CD2CD3)(CD3)3Sb[Pd(dmit)2]2 and compared the result with pristine (CH3CH2)(CH3)3Sb[Pd(dmit)2]2and partially deuterated (CH3CH2)(CD3)3Sb[Pd(dmit)2]2. We found the highest value of electronic heat capacity at low temperature in full deuterated sample and each behavior of heat capacity is different from each other. Since the absence of rotation phenomena in Et group was already confirmed in partially deuterated sample, the larger value of heat capacity of full deuterated sample than that of partially deuterated sample is due to the difference of electronic heat capacity. This fact suggests that in this compound the electronic structure was tuned by the deuteration of cation. The really sensitive behavior of quantum spin liquid state in Pd(dmit)2 system was also demonstrated.
Fig. 1. The chemical structure of Pd(dmit)2 and EtxMe4−xSb+. The size of cation is becomes larger with increasing x. Three types of electronic ground states are obtained by each cation.
Fig. 2. The low temperature heat capacities of full deuterated sample, partially deuterated sample and pristine sample using CpT−1 vs T2 plot. The large upturn below 1 K is only observed in pristine sample. The systematic increasing of heat capacity with increasing deuteron suggests that the deuteration of cation in this system affect to the electronic property.