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Lai, You

Publications and source records attributed to Lai, You.

Electronic landscape of the f -electron intermetallics with the ThCr 2 Si 2 structure

Although strongly correlated f -electron systems are well known as reservoirs for quantum phenomena, a persistent challenge is to design specific states. What is often missing are simple ways to determine whether a given compound can be expected to exhibit certain behaviors and what tuning vector(s) would be useful to select the ground state. In this review, we address this question by aggregating information about Ce, Eu, Yb, and U compounds with the ThCr 2 Si 2 structure. We construct electronic/magnetic state maps that are parameterized in terms of unit cell volumes and d -shell filling, which reveals useful trends including that (i) the magnetic and nonmagnetic examples are well separated, and (ii) the crossover regions harbor the examples with exotic states. These insights are used to propose structural/chemical regions of interest in these and related materials, with the goal of accelerating discovery of the next generation of f -electron quantum materials.

42 ENGINEERING↗

Defect-driven ferrimagnetism and hidden magnetization in MnBi 2 Te 4

MnBi 2 Te 4 (MBT) materials are promising antiferromagnetic topological insulators in which field-driven ferromagnetism is predicted to cause a transition between axion insulator and Weyl semimetallic states. However, the presence of antiferromagnetic coupling between Mn/Bi antisite defects and the main Mn layer can reduce the low-field magnetization, and it has been shown that such defects are more prevalent in the structurally identical magnetic insulator MnSb 2 Te 4 (MST). We use high-field magnetization measurements to show that the magnetization of MBT and MST occur in stages and full saturation requires fields of ~60 T. As a consequence, the low-field magnetization plateau state in MBT, where many determinations of the quantum anomalous Hall state are studied, actually consists of ferrimagnetic septuple blocks containing both uniform and staggered magnetization components.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Superstructures and Superconductivity Linked with Pd Intercalation in Nb 2 Pd x Se 5

Single crystals of Nb 2 Pd x Se 5 have been grown covering a broad range of palladium stoichiometries, from x = 0.68 to x = 0.95 (Pd2 occupancies 0.36 and 0.90 respectively). Miscibility gaps in the Pd stoichiometry range are related to superstructures resulting from staged filling and ordering of the partially filled Pd atom site (Pd2, Wyckoff site 2a). For Pd2 near 1/2 occupancy, a superstructure based on an incommensurate occupation wave with modulation along the monoclinic b-axis is identified. Here, a superconducting dome is found for Pd2 occupancies above 0.58, with maximum Tc for Pd2 occupancy of approximately 2/3. DFT calculations for the fully and 1/2 occupied Pd2 site show that Nb 2 Pd x Se 5 can be considered an intercalation compound for Pd2 occupancy above the minimum required for structural stability.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗