Self-consistent local equilibrium model for density profile and distribution of dissipative currents in a Hall bar under strong magnetic fields -: art. no. 115327
Self-consistent local equilibrium model for density profile and distribution of dissipative currents in a Hall bar under strong magnetic fields -: art. no. 115327
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DOI：
10.1103/physrevb.67.115327
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发表时间：
2003-03-15
影响因子：
3.7
通讯作者：
Gerhardts, RR
中科院分区：
文献类型：
--
作者：
Güven, K;Gerhardts, RR
最近对强磁场中霍尔棒上的静电势变化的空间分辨测量表明，霍尔棒边缘附近的载流带和不可压缩带之间存在明显的关联，这不能根据现有的平衡理论来理解。为了解释这些实验，我们将自洽计算总热平衡中静电势和电子密度的Thomas-Fermi-Poisson方法推广到局部平衡理论，该理论允许我们将电化学势的有限梯度视为存在耗散时的电流驱动力。对于(局域)Landau能级填充因子的整数值，传统的纵向电导率模型表明，电流密度集中在不可压缩条带附近，其位置和宽度取决于外加电流，这与实验明显一致。
Recent spatially resolved measurements of the electrostatic-potential variation across a Hall bar in strong magnetic fields, which revealed a clear correlation between current-carrying strips and incompressible strips expected near the edges of the Hall bar, cannot be understood on the basis of existing equilibrium theories. To explain these experiments, we generalize the Thomas-Fermi-Poisson approach for the self-consistent calculation of electrostatic potential and electron density in total thermal equilibrium to a local equilibrium theory that allows us to treat finite gradients of the electrochemical potential as driving forces of currents in the presence of dissipation. A conventional conductivity model with small values of the longitudinal conductivity for integer values of the (local) Landau-level filling factor shows that, in apparent agreement with experiment, the current density is localized near incompressible strips, whose location and width in turn depend on the applied current.