Anisotropic Fermi Surfaces, Electrical Transport, and Two-Dimensional Fermi Liquid Behavior in Layered Ternary Boride MoAlB

Abstract

We report a study of fermiology, electrical anisotropy, and Fermi liquid properties in the layered ternary boride MoAlB, which could be peeled into two-dimensional (2D) metal borides (MBenes). By studying the quantum oscillations in comprehensive methods of magnetization, magnetothermoelectric power, and torque with the first-principle calculations, we reveal three types of bands in this system, including two 2D-like electronic bands and one complex three-dimensional-like hole band. Meanwhile, a large out-of-plane electrical anisotropy (ρbb /ρaa ∼ 1100 and ρbb /ρcc ∼ 500, at 2 K) was observed, which is similar to those of the typical anisotropic semimetals but lower than those of some semiconductors (up to 105). After calculating the Kadowaki–Woods ratio (KWR = A/γ 2), we observed that the ratio of the in-plane A a,c /γ 2 is closer to the universal trend, whereas the out-of-plane A b /γ 2 severely deviates from the universality. This demonstrates a 2D Fermi liquid behavior. In addition, MoAlB cannot be unified using the modified KWR formula like other layered systems (Sr2RuO4 and MoOCl2). This unique feature necessitates further exploration of the Fermi liquid property of this layered molybdenum compound.