论文标题
LAPD $ _3 $ S $ _4 $的阴离子框架的键合和电子性质
Bonding and Electronic Nature of the Anionic Framework in LaPd$_3$S$_4$
论文作者
论文摘要
双狄拉克材料是物质的拓扑阶段，在这种阶段中，非符号对称性的电子退化性比正常预期的高达八倍。立方钯青铜napd $ _3 $ o $ _4 $和lapd $ _3 $ s $ _4 $由PD $ _3 $ _3 $ x $ _4 $（x = o，s）阴离子框架（x = o，s）的阴离子框架（a = a = na，la）。这些材料最近在计算上被识别为具有八倍的费米子。在这里，我们报告了LAPD $ _3 $ S $ _4 $的单晶和电子特性的准备。降至t = 0.45 k的测量值，在最高$μ$ 0H = 65 t的磁场中，在存在稀释磁性杂质的情况下与狄拉克金属的正常费米液体物理相一致。通过分析特定的热量，磁化测量和与密度功能理论（DFT）计算的比较，进一步证实了这种解释。 Through a bonding analysis of the DFT electronic structure of NaPd$_3$O$_4$ and LaPd$_3$S$_4$, we identify the origin of the stability of the anionic Pd$_3$X$_4$ framework at higher electron counts for X = S than X = O, and propose chemical tuning strategies to enable shifting the 8-fold fermion points to the Fermi level.
Double Dirac materials are a topological phase of matter in which a non-symmorphic symmetry enforces greater electronic degeneracy than normally expected up to eightfold. The cubic palladium bronzes NaPd$_3$O$_4$ and LaPd$_3$S$_4$ are built of Pd$_3$X$_4$ (X = O, S) anionic frameworks that are ionically bonded to A cations (A = Na, La). These materials were recently identified computationally as harboring eightfold fermions. Here we report the preparation of single crystals and electronic properties of LaPd$_3$S$_4$. Measurements down to T = 0.45 K and in magnetic fields up to $μ$0H = 65 T are consistent with normal Fermi liquid physics of a Dirac metal in the presence of dilute magnetic impurities. This interpretation is further confirmed by analysis of specific heat, magnetization measurements and comparison to density functional theory (DFT) calculations. Through a bonding analysis of the DFT electronic structure of NaPd$_3$O$_4$ and LaPd$_3$S$_4$, we identify the origin of the stability of the anionic Pd$_3$X$_4$ framework at higher electron counts for X = S than X = O, and propose chemical tuning strategies to enable shifting the 8-fold fermion points to the Fermi level.
