Effect of disorder in an orbitally ordered Jahn-Teller insulator
Effect of disorder in an orbitally ordered Jahn-Teller insulator
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DOI：
10.1103/physrevb.75.014209
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发表时间：
2006-09
影响因子：
3.7
通讯作者：
Sanjeev Kumar;A. Kampf;P. Majumdar
中科院分区：
文献类型：
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作者：
Sanjeev Kumar;A. Kampf;P. Majumdar
我们使用最近开发的蒙特卡罗技术，研究了在存在猝灭无序的情况下与 Jahn-Teller 畸变耦合的 $e_g$ 电子的二维、两带双交换模型。在没有无序的情况下，低温下的半填充系统是一个轨道有序的铁磁绝缘体，具有交错的 Jahn-Teller 畸变模式。我们研究了到轨道无序相的有限温度转变，并揭示了中间耦合系统和强耦合系统之间的质的差异，包括前一种情况下的热驱动绝缘体到金属的交叉。在无序存在的情况下，长程轨道有序性受到抑制，并且系统表现出亚稳态的趋势，该状态由包围轨道有序域的轨道无序条纹状结构组成。
We study a two dimensional, two-band double-exchange model for $e_g$ electrons coupled to Jahn-Teller distortions in the presence of quenched disorder using a recently developed Monte-Carlo technique. In the absence of disorder the half-filled system at low temperatures is an orbitally ordered ferromagnetic insulator with a staggered pattern of Jahn-Teller distortions. We examine the finite temperature transition to the orbitally disordered phase and uncover a qualitative difference between the intermediate and strongly coupled systems, including a thermally driven insulator to metal crossover in the former case. Long range orbital order is suppressed in the presence of disorder and the system displays a tendency towards metastable states consisting of orbitally disordered stripe-like structures enclosing orbitally ordered domains.