Metal-to-metal transition and heavy-electron state in Nd$_4$Ni$_3$O$_{10-δ}$

Abstract

The trilayer nickelate Nd4Ni3O 10−δ (δ ≈ 0.15) was investigated by the measurements of x-ray diffraction, electrical resistivity, magnetic susceptibility, and heat capacity. The crystal structure data suggest a higher Ni valence in the inner perovskite-like layer. At ambient pressure the resistivity shows a jump at 162 K, indicating a metal-to-metal transition (MMT). The MMT is also characterized by a magnetic susceptibility drop, a sharp specific-heat peak, and an isotropic lattice contraction. Below ∼ 50 K, a resistivity upturn with a logT dependence shows up, accompanying with a negative thermal expansion. External hydrostatic pressure suppresses the resistivity jump progressively, coincident with the diminution of the logT behavior. The low-temperature electronic specific-heat coefficient is extracted to be ∼ 150 mJ K −2 mol-fu −1 , equivalent to ∼ 50 mJ K −2 mol-Ni −1 , indicating an unusual heavy-electron correlated state. The novel heavy-electron state as well as the logarithmic temperature dependence of resistivity is explained in terms of the Ni 3+ centered Kondo effect in the inner layer of the (NdNiO3)3 trilayers.

Infrared spectroscopic study of Nd<sub>4</sub>Ni<sub>3</sub>O<sub>10</sub>

“…随后, 人们在镧系 的无限层镍氧化物薄膜, 如(La/Pr) 1−x Sr x NiO 2 [21][22][23] 和 La 1−x Ca x NiO 2 [24] 等, 以及五层的镍氧化物Nd 6 Ni 5 O 12 [25] 薄膜中也发现了超导电性. 中山大学的王猛小组 [6] 通 中, 人们发现都存在一个金属到金属的转变 [5,[7][8][9][10][11] , 引 起了众多关注. 这个转变被普遍认为是电荷密度波的 不稳定所造成的 [7] , 但其中具体的物理机制还不明确, 需要进一步研究.…”

“…随着无限层镍氧化物薄膜中超导电性的发现, 大家才又将目光投向这种材料. 浙江大学的曹光旱小 组 [9] 测量了Nd 4 Ni 3 O 10 的输运性质和XRD结果, 发现其 中金属到金属的转变伴随着磁化率下降、尖锐的比热 峰和各向同性晶格收缩等特征. 苏黎世大学的Huangfu 等人 [10] 发现,…”