Zhang T X, Samanta B, Wang J, Georgescu A B, Fertig H A, Zhang S X
Department of Physics, Indiana University, Bloomington, Indiana 47405, United States.
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.
ACS Appl Mater Interfaces. 2024 Oct 9;16(40):54837-54846. doi: 10.1021/acsami.4c11537. Epub 2024 Sep 28.
The PbSnTe family of compounds possess a wide range of intriguing and useful physical properties, including topologically protected surface states, robust ferroelectricity, remarkable thermoelectric properties, and potential topological superconductivity. Compared to bulk crystals, one-dimensional (1D) nanowires (NWs) offer a unique platform to enhance the functional properties and enable new capabilities, e.g., to realize 1D Majorana zero modes for quantum computations. However, it has been challenging to achieve controlled synthesis of ultrathin PbSnTe (0 ≤ ≤ 1) nanowires in the truly 1D region. In this work, we report on a Au-catalyzed vapor-liquid-solid (VLS) growth of remarkably thin (20-30 nm) and sufficiently long (several to tens of micrometers) PbSnTe nanowires of high single-crystalline quality in a controlled fashion. This controlled growth was achieved by enhancing the incorporation of Te into the Au catalyst particle to facilitate the precipitation of the Sn/Pb species and suppress the enlargement of the particle, which we identified as a major challenge for the growth of ultrathin nanowires. Our growth strategy can be easily extended to other compound and alloy nanowires, where the constituent elements have different incorporation rates into the catalyst particle. Furthermore, the growth of thin PbSnTe nanowires enabled strain-dependent electrical transport measurements, which shows an enhancement of electrical resistance and ferroelectric transition temperature induced by uniaxial tensile strain along the nanowire axial direction, consistent with density functional theory calculations of the structural phase stability.
铅锡碲化合物家族具有一系列引人入胜且有用的物理性质，包括拓扑保护的表面态、强大的铁电性、显著的热电性质以及潜在的拓扑超导性。与块状晶体相比，一维（1D）纳米线（NWs）提供了一个独特的平台来增强功能特性并实现新的能力，例如实现用于量子计算的一维马约拉纳零模。然而，在真正的一维区域实现超薄铅锡碲（0≤≤1）纳米线的可控合成一直具有挑战性。在这项工作中，我们报道了一种通过金催化的气-液-固（VLS）生长方法，以可控方式生长出高质量的极细（20 - 30纳米）且足够长（几到几十微米）的单晶铅锡碲纳米线。这种可控生长是通过增强碲向金催化剂颗粒中的掺入来实现的，以促进锡/铅物种的沉淀并抑制颗粒的增大，我们将其确定为超薄纳米线生长的一个主要挑战。我们的生长策略可以很容易地扩展到其他化合物和合金纳米线，其中组成元素向催化剂颗粒中的掺入速率不同。此外，薄铅锡碲纳米线的生长使得能够进行应变依赖的电输运测量，结果表明沿纳米线轴向的单轴拉伸应变会导致电阻和铁电转变温度升高，这与结构相稳定性的密度泛函理论计算结果一致。
