1] Korea Research Institute of Standards and Science, Daejeon 305-340, Republic of Korea [2].
Nat Mater. 2013 Oct;12(10):913-8. doi: 10.1038/nmat3708. Epub 2013 Jul 14.
Heat is a familiar form of energy transported from a hot side to a colder side of an object, but not a notion associated with microscopic measurements of electronic properties. A temperature difference within a material causes charge carriers, electrons or holes to diffuse along the temperature gradient inducing a thermoelectric voltage. Here we show that local thermoelectric measurements can yield high-sensitivity imaging of structural disorder on the atomic and nanometre scales. The thermopower measurement acts to amplify the variations in the local density of states at the Fermi level, giving high differential contrast in thermoelectric signals. Using this imaging technique, we uncovered point defects in the first layer of epitaxial graphene, which generate soliton-like domain-wall line patterns separating regions of the different interlayer stacking of the second graphene layer.
热是一种常见的能量传递形式，从物体的热侧传递到冷侧，但不是与微观电子性质测量相关的概念。材料内部的温差会导致载流子（电子或空穴）沿着温度梯度扩散，从而产生热电电压。在这里，我们展示了局部热电测量可以对原子和纳米尺度的结构无序进行高灵敏度成像。热电功率测量可以放大费米能级处局部态密度的变化，从而在热电信号中产生高差分对比度。使用这种成像技术，我们在外延石墨烯的第一层中发现了点缺陷，这些缺陷产生了类孤子的畴壁线图案，将第二层石墨烯不同的层间堆叠区域分隔开来。
