A Monoclinic Variant of ThCr2Si2-Type BaAg2Sb2: Electronic Structure and Physical Properties
Hanlin Wu1, Wenhao Liu1, Nikhil Dhale1
1Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States.
Abstract:
A monoclinic variant of the ThCr2Si2-type structure of BaAg2Sb2, with the Pearson symbol mC10, has been discovered. Its crystal structure was determined by single-crystal X-ray diffraction, with space group C2/m (No. 12), and lattice parameters a = 12.441(4) Å, b = 4.790(2) Å, c = 4.876(2) Å, β = 112.88(1)°, and V = 268.8(6) Å3. It features tetragonally coordinated Ag2Sb2 layers that are distorted and stacked along the crystallographic a-axis, with a strong interlayer Sb-Sb bond. Transport measurements reveal a non-negligible magnetoresistivity of up to 18%, with cusp-like behavior. Electron-dominated charge carriers over a broad temperature range are also verified by Hall measurements. Moreover, temperature-dependent resistivity behavior exhibits a small deviation from the conventional Bloch-Grüneisen model, which is likely due to the brink of a possible Lifshitz transition, as revealed by first-principles calculations.
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