论文标题
由顶层厚度控制的纳米级摩擦在[lamno $ _ {3} $] $ _ {m} $/[srmno $ _ {3} $] $ _ {n} $ superlattices
Nanoscale friction controlled by top layer thickness in [LaMnO$_{3}$]$_{m}$/[SrMnO$_{3}$]$_{n}$ superlattices
论文作者
论文摘要
我们在七个[lamno $ _ {3} $] $ _ {m} $/[srmno $ _ {3} $] $ _ {n} $ superlattices具有不同层厚度的层。我们观察到，摩擦力和摩擦系数最初会随着LAMNO3顶层厚度的增加而增加，然后在顶层厚度超过几纳米时饱和。这些观察结果清楚地表明，滑动摩擦会受地下材料特性的影响到几种纳米的深度，并且不仅取决于触点接口中的动力学。我们认为，地下耗散的能量受AFM尖端以下弹性紧张的体积的阻尼来控制，这是我们通过热弹性估算的效果。我们的超晶格的摩擦与热电阻率之间没有相关性，此外，高频声子和热传导在确定摩擦方面不起作用。因此，我们的观察结果表明，摩擦可以通过地下材料特性量身定制。
We conducted lateral force microscopy measurements on seven [LaMnO$_{3}$]$_{m}$/[SrMnO$_{3}$]$_{n}$ superlattices with varied layer thicknesses. We observe that the friction forces and the friction coefficients initially increase with increasing LaMnO3 top layer thickness, followed by saturation when the top layer thickness exceeds a few nanometers. These observations clearly demonstrate that sliding friction is affected by sub-surface material properties to a depth of several nanometers and is not just determined by dynamics in the contact interface. We argue that the sub-surface dissipated energy is governed by damping in the elastically strained volume below the AFM tip, an effect which we estimate via thermoelasticity. The absence of a correlation between friction and the thermal resistivity of our superlattices shows furthermore that high-frequency phonons and heat conduction do not play a role in determining friction. Our observations thus demonstrate that friction can be tailored by sub-surface material properties.
