Bhattacharya Anand, Skinner Brian, Khalsa Guru, Suslov Alexey V
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Massachusetts Institute of Technology, 77 Mass Ave, Cambridge, Massachusetts 02139, USA.
Nat Commun. 2016 Sep 29;7:12974. doi: 10.1038/ncomms12974.
When an electronic system is subjected to a sufficiently strong magnetic field that the cyclotron energy is much larger than the Fermi energy, the system enters the extreme quantum limit (EQL) and becomes susceptible to a number of instabilities. Bringing a three-dimensional electronic system deeply into the EQL can be difficult however, since it requires a small Fermi energy, large magnetic field, and low disorder. Here we present an experimental study of the EQL in lightly-doped single crystals of strontium titanate. Our experiments probe deeply into the regime where theory has long predicted an interaction-driven charge density wave or Wigner crystal state. A number of interesting features arise in the transport in this regime, including a striking re-entrant nonlinearity in the current-voltage characteristics. We discuss these features in the context of possible correlated electron states, and present an alternative picture based on magnetic-field induced puddling of electrons.
当一个电子系统受到足够强的磁场作用，使得回旋加速器能量远大于费米能量时，该系统进入极端量子极限（EQL），并变得易于出现多种不稳定性。然而，要将一个三维电子系统深入带入EQL可能很困难，因为这需要小的费米能量、强磁场和低无序度。在此，我们展示了对轻掺杂钛酸锶单晶中EQL的实验研究。我们的实验深入探究了理论长期以来预测存在相互作用驱动的电荷密度波或维格纳晶体态的区域。在该区域的输运中出现了许多有趣的特征，包括电流 - 电压特性中显著的重入非线性。我们在可能的关联电子态的背景下讨论这些特征，并基于磁场诱导的电子聚集提出了一种不同的图景。
