The nanoscopic magnetic texture forming in a monolayer of iron on the (111) surface of iridium, Fe/Ir(111), is spatially modulated and uniaxially incommensurate with respect to the crystallographic periodicities. As a consequence, a low-energy magnetic excitation is expected that corresponds to the sliding of the texture along the incommensurate direction, i.e., a phason mode, which we explicitly confirm with atomistic spin simulations. Using scanning tunneling microscopy (STM), we succeed to observe this phason mode experimentally. It can be excited by the STM tip, which leads to a random telegraph noise in the tunneling current that we attribute to the presence of two minima in the phason potential due to the presence of disorder in our sample. This provides the prospect of a floating phase in cleaner samples and, potentially, a commensurate-incommensurate transition as a function of external control parameters.

在铱（111）表面上的单层铁中形成的纳米级磁性结构，Fe/Ir（111），是空间调制的并且相对于晶体周期性是单轴不相称的。因此，预计会出现与纹理沿不相称方向滑动相对应的低能磁激发，即相子模式，我们通过原子自旋模拟明确证实了这一点。使用扫描隧道显微镜（STM），我们成功地通过实验观察到了这种相子模式。它可以被 STM 尖端激发，这会导致隧道电流中出现随机电报噪声，我们将其归因于由于样本中存在无序而导致相子电位中存在两个最小值。这提供了在更清洁的样品中出现浮动相的前景，并且可能提供作为外部控制参数的函数的相称-不相称转变。