arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2103.01332cond-mat.mes-hallcond-mat.mtrl-sci
收藏

二维金属PdCoO2中的定向弹道输运

Directional ballistic transport in the two-dimensional metal PdCoO2

Maja D. Bachmann, Aaron L. Sharpe, Arthur W. Barnard, Carsten Putzke, Thomas Scaffidi, Nabhanila Nandi, Seunghyun Khim, Markus Koenig, David Goldhaber- Gordon, … 展开作者

Maja D. Bachmann, Aaron L. Sharpe, Arthur W. Barnard, Carsten Putzke, Thomas Scaffidi, Nabhanila Nandi, Seunghyun Khim, Markus Koenig, David Goldhaber- Gordon, Andrew P. Mackenzie, Philip J. W. Moll

摘要:

在理想化的无限晶体中,材料性质受其晶胞的对称性约束。当然,点群对称性会被任何有限晶体的样品形状破坏,但这在宏观金属中通常是不可观察的。为了检测这种金属中形状诱导的对称性降低,需要来自各向异性费米表面的长寿命体态。在这里,我们展示了如何强烈的费米面和长准粒子平均自由程的微观结构中存在的PdCoO2产生的平面电阻率各向异性,是禁止对称性的无限六边形晶格。使用聚焦离子束(FIB)铣削从单晶雕刻出比平均自由程窄的条形传输器件,使得低温下的弹道载流子频繁地与限定沟道的两个侧壁碰撞。出现了两个禁戒输运特征:面内电阻率各向异性超过2倍,零磁场下出现横向电压。通过弹道蒙特卡罗模拟和玻尔兹曼方程的数值解,我们鲁棒地识别出通道方向作为对称性破缺的来源。

英文摘要:

In an idealized infinite crystal, the material properties are constrained by the symmetries of its unit cell. Naturally, the point-group symmetry is broken by the sample shape of any finite crystal, yet this is commonly unobservable in macroscopic metals. To sense the shape-induced symmetry lowering in such metals, long-lived bulk states originating from anisotropic Fermi surfaces are needed. Here we show how strongly facetted Fermi surfaces and long quasiparticle mean free paths present in microstructures of PdCoO2 yield an in-plane resistivity anisotropy that is forbidden by symmetry on an infinite hexagonal lattice. Bar shaped transport devices narrower than the mean free path are carved from single crystals using focused ion beam (FIB) milling, such that the ballistic charge carriers at low temperatures frequently collide with both sidewalls defining a channel. Two symmetry-forbidden transport signatures appear: the in-plane resistivity anisotropy exceeds a factor of 2, and transverse voltages appear in zero magnetic field. We robustly identify the channel direction as the source of symmetry breaking via ballistic Monte- Carlo simulations and numerical solution of the Boltzmann equation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑