NUS physicists have discovered a new form of ferroelectricity in a single-element bismuth monolayer that can produce regular and reversible dipole moments. This could be used for applications like non-volatile memories and electronic sensors. This breakthrough was made possible by harnessing the unique properties of two-dimensional materials, known for their extraordinary mechanical and electrical properties.
The team combined a bismuth monolayer with a thin layer of metal oxide to create a van der Waals heterostructure that enabled them to observe ferroelectricity in single layers. This is the first time such effects have been observed in bismuth monolayers, paving the way for potential applications such as non-volatile memories, logic gates and other electronic components. The study has demonstrated that these two-dimensional materials can be used for various novel technological applications.
By controlling the dipole moments of these nanoscale structures using external electric fields, it may be possible to create new types of memory devices or sensors capable of storing information without consuming energy when not operating. Moreover, this discovery could also pave the way towards developing better transistors and other electronic components based on 2D materials with enhanced nanoscale performance characteristics.
Ferroelectric materials are typically used as capacitors in electronic devices like mobile phones and other consumer electronics. These components use the polarization reversal of ferroelectric material to change the electric field inside them. This allows for more efficient data storage since a larger amount of information can be stored in smaller areas due to the higher resolution of polarization. Ferroelectrics are also widely used in sensors which measure pressure or displacement by detecting changes in their electrical properties when external forces act upon them. In addition, they have been explored for use in applications such as ultrasound imaging and optical displays.
Recent research focuses on developing 2D ferroelectric materials, such as halide perovskites, 2D transition metal dichalcogenides (TMDCs), and two-dimensional binary oxides. Halide perovskite thin films display a high Curie temperature and large polarization, promising for future technologies. The TMDCs also show remarkable potential due to their unique structural flexibility enabling manipulation of the bandgap through doping or tuning the number of layers in heterostructures.
Finally, two-dimensional binary oxide systems demonstrate many phase transitions in their crystal structures that can be used for engineering polarization by applying external electric fields. All these new materials provide an attractive platform for developing neuromorphic synapse devices with improved performance over traditional 3D counterparts.
The team’s research results have been published in the world-renowned scientific journal Nature Communications. The article “Induced ferroelectricity in two-dimensional black phosphorus-like bismuth” was supported by the National Science Foundation and other funds from NUS. Professor Wee commented that this breakthrough discovery could open up more opportunities for the future development of next-generation electronic devices, such as memory storage devices and logic gates, to name a few. This would improve performance, faster speed and reduce power consumption for these electronic applications.
Ferroelectricity is advantageous for its manipulation by only the electric field. This makes it more suitable to be contained in integrated circuit devices. Many studies found it possible to manipulate other material attributes by coupling ferroelectricity with these properties.
The study’s lead author, Dr Jian Gou, says that their research has found evidence of a new type of polarization in BP-Bi that could significantly impact the material’s optical and electrical properties. This discovery could lead to important advances in studying and designing novel ferroelectric materials.