Two-Dimensional Electron Gases at Oxide Interfaces
- PDF / 824,013 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 29 Downloads / 209 Views
Two-Dimensional
Electron Gases at Oxide Interfaces
J. Mannhart, D.H.A. Blank, H.Y. Hwang, A.J. Millis, and J.-M. Triscone Abstract Two-dimensional electron gases (2DEGs) based on conventional semiconductors such as Si or GaAs have played a pivotal role in fundamental science and technology. The high mobilities achieved in 2DEGs enabled the discovery of the integer and fractional quantum Hall effects and are exploited in high-electron-mobility transistors. Recent work has shown that 2DEGs can also exist at oxide interfaces. These electron gases typically result from reconstruction of the complex electronic structure of the oxides, so that the electronic behavior of the interfaces can differ from the behavior of the bulk. Reports on magnetism and superconductivity in oxide 2DEGs illustrate their capability to encompass phenomena not shown by interfaces in conventional semiconductors. This article reviews the status and prospects of oxide 2DEGs.
Introduction Today, the operation of almost any semiconducting device relies on the use of interfaces. Although semiconducting technology started to utilize interfaces more than 50 years ago, an analogous development is taking off today. Advances in the heteroepitaxy of complex oxides now provide the possibility of fabricating interfaces in oxides, including oxides with strongly correlated electrons, with atomic precision. Such interfaces can generate electron systems that nature does not produce in the bulk. The electrons interact and order at the interfaces in unique ways, so that, for example, field-effect transistors using phase transitions, novel types of quantum Hall systems, and unique superconductors can be obtained. Wellcontrolled interfaces based on oxide materials have been fabricated and are being used for a possible new generation of oxide electronic devices. They complement the interface-based bulk oxide capacitors and varistors that have been a great commercial success for many decades. The defining property of interfaces—the simple fact that they connect different materials—creates new possibilities for generating novel electronic phases.
The challenges to the materials scientists and physicists are enormous. Yet, by offering tremendous flexibility, such interfaces create emerging possibilities in designing new electronic systems. Herein, we provide an overview of a particularly interesting development that recently occurred in this field: the generation of ultrathin, or even two-dimensional, electron gases at oxide interfaces.
The realization of two-dimensional electron gases (2DEGs) in semiconductor interfaces based on Si or on III–V compounds has led to tremendous developments and successes in both understanding fundamental physics and developing new devices. As a fruit of efforts that started in the 1960s, 2DEGs with typical carrier densities ranging from 1010/cm2 to 1012/cm2 can be generated at a single heterojunction (interface between two different materials) or in doped heterostructures that form superlattices (periodic arrays of interfaces). As sh
Data Loading...
