Syers Paul, Kim Dohun, Fuhrer Michael S, Paglione Johnpierre
Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA.
Phys Rev Lett. 2015 Mar 6;114(9):096601. doi: 10.1103/PhysRevLett.114.096601. Epub 2015 Mar 3.
Bulk and surface state contributions to the electrical resistance of single-crystal samples of the topological Kondo-insulator compound SmB_{6} are investigated as a function of crystal thickness and surface charge density, the latter tuned by ionic liquid gating with electrodes patterned in a Corbino disk geometry on a single (100) surface. By separately tuning bulk and surface conduction channels, we show conclusive evidence for a model with an insulating bulk and metallic surface states, with a crossover temperature that depends solely on the relative contributions of each conduction channel. The surface conductance, on the order of 100 e^{2}/h, exhibits a field-effect mobility of 133 cm^{2}/Vs and a large carrier density of ∼2×10^{14} cm^{-2}, in good agreement with recent photoemission results. With the ability to gate modulate surface conduction by more than 25%, this approach provides promise for both fundamental and applied studies of gate-tuned devices structured on bulk crystal samples.
研究了拓扑近藤绝缘体化合物SmB₆单晶样品的体相和表面态对电阻的贡献，该贡献是晶体厚度和表面电荷密度的函数，后者通过在单个（100）表面上以科贝诺盘几何形状图案化的电极进行离子液体门控来调节。通过分别调节体相和表面传导通道，我们给出了确凿证据，证明了一个具有绝缘性体相和金属性表面态的模型，其交叉温度仅取决于每个传导通道的相对贡献。表面电导约为100 e²/h，场效应迁移率为133 cm²/Vs，载流子密度约为2×10¹⁴ cm⁻²，与最近的光电子能谱结果吻合良好。由于能够通过门控调制使表面传导变化超过25%，这种方法为基于体相晶体样品构建的门控器件的基础研究和应用研究带来了希望。
