论文标题
BA $ _2 $ MGREO $ _6 $的实验和理论热力学研究 - 在Jahn-Teller效应的基础状态
Experimental and theoretical thermodynamic studies in Ba$_2$MgReO$_6$ -- the ground state in the context of Jahn-Teller effect
论文作者
论文摘要
我们使用特定的热量测量值和密度函数计算的组合，解决了5 $ d^1 $ re $^{6+} $ ion of double Perovskite ba $ _ {2} $ _ {2} $ _ {2} $ ion in 5 $ d^1 $ re $^{6+} $ ion的基态多重的堕落的堕落。对于ba $ _ {2} $ mgreo $ _ {6} $，以前已经提出了两个不同的基态多重 - 四重奏（带有脱落$ n $ = 4）[1]和doublet（$ n $ = 2）[2] [2]。在这里，我们采用两种独立的方法来估计热容量数据中的声子贡献，以获得磁熵$ s_ {mag} $，这反映了基态多重n $ n $ tifun $ s_ {mag} = r $ ln $ n $的脱落。在这两种情况下，我们都可以更好地适合$ s_ {mag} = r $ ln2，指示$ n $ = 2级别的证据在2到120〜K。 Ba $ _ {2} $ mgreo $ _ {6} $中基态多重的详细性质仍然是一个空旷的问题。
We address the degeneracy of the ground state multiplet on the 5$d^1$ Re$^{6+}$ ion in double perovskite Ba$_{2}$MgReO$_{6}$ using a combination of specific heat measurements and density functional calculations. For Ba$_{2}$MgReO$_{6}$, two different ground state multiplets have previously been proposed - a quartet (with degeneracy $N$=4) [1] and a doublet ($N$=2) [2]. Here we employ two independent methods for the estimation of phonon contribution in heat capacity data to obtain the magnetic entropy $S_{mag}$, which reflects the degeneracy of the ground state multiplet $N$ through $S_{mag}=R$ln$N$. In both cases, we obtain a better fit to $S_{mag}=R$ln2 indicating evidence of $N$=2 degeneracy in the range from 2 to 120~K. The detailed nature of the ground state multiplet in Ba$_{2}$MgReO$_{6}$ remains an open question.
