Zhang W Q, Shen H Z, Yi X X
Center for Quantum Sciences, Northeast Normal University, Changchun, 130117, China.
Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun, 130024, China.
Sci Rep. 2017 Nov 24;7(1):16243. doi: 10.1038/s41598-017-16061-6.
The response of the open two-band system to external fields would in general be different from that of a strictly isolated one. In this paper, we systematically study the Hall conductance of a two-band model under the influence of its environment by treating the system and its environment on equal footing. In order to clarify some well-established conclusions about the Hall conductance, we do not use the rotating wave approximation (RWA) in obtaining an effective Hamiltonian. Specifically, we first derive the ground state of the whole system (the system plus the environment) beyond the RWA, then calculate an analytical expression for Hall conductance of this open system in the ground state. We apply the expression to two examples, including a magnetic semiconductor with Rashba-type spin-orbit coupling and an electron gas on a square two-dimensional lattice. The calculations show that the transition points of topological phase are robust against the environment. Our results suggest a way to the controlling of the whole system response, which has potential applications for condensed matter physics and quantum statistical mechanics.
一般来说，开放双能带系统对外部场的响应会与严格孤立的系统不同。在本文中，我们通过平等对待系统及其环境，系统地研究了双能带模型在其环境影响下的霍尔电导。为了阐明一些关于霍尔电导的既定结论，我们在获得有效哈密顿量时未使用旋转波近似（RWA）。具体而言，我们首先在不采用RWA的情况下推导出整个系统（系统加环境）的基态，然后计算该开放系统基态霍尔电导的解析表达式。我们将该表达式应用于两个例子，包括具有Rashba型自旋轨道耦合的磁性半导体和方形二维晶格上的电子气。计算结果表明，拓扑相的转变点对环境具有鲁棒性。我们的结果提出了一种控制整个系统响应的方法，这在凝聚态物理和量子统计力学中具有潜在应用。
