New Quantum Tricks in Nitride Materials

Published November 22, 2021

(a) Layer structure of the epitaxial nitride heterostructure. (b) High-resolution transmission electron microscopy image of the semiconductor /superconductor interface.

Gallium nitride (GaN) and Niobium nitride (NbN) are widely used in today's technologies: GaN is used to make blue LEDs and high-frequency transistors while NbN is used to make infrared light detectors. This experiment explores whether a nitride-based device may be relevant for quantum technologies of the future.

What did scientists discover?

A new device structure that combines a nitride semiconductor with a nitride superconductor is shown to exhibit two quantum states simultaneously - the quantum Hall state and superconductivity - that typically do not coexist.

Why is this important?

Researchers studied two conventional materials: GaN (a semiconductor) and NbN (a superconductor). If the semiconductor enters the quantum Hall state in proximity to a superconductor, one could achieve topological superconductivity, which can be used for quantum computing.

A challenge with this approach is that the quantum Hall states in a semiconductor typically require high magnetic fields, but superconductivity is quenched at high magnetic fields, making coexistence difficult. By demonstrating that this nitride structure can host both phenomena simultaneously, this research demonstrates that the "old dogs" (i.e. GaN and NbN) can in fact learn a new trick. The nitride material system is among the most widely used and mature semiconductor technologies, making it very appealing for use in quantum computing applications.

Who did the research?

P. Dang¹, G. Khalsa¹, C. S. Chang¹, D. S. Katzer², N. Nepal², B. P. Downey², V. D. Wheeler², A. Suslov³, A. Xie⁴, E. Beam⁴, Y. Cao⁴, C. Lee⁴, H. G. Xing¹, D. J. Meyer², D. Jena¹

¹Cornell University; ²Naval Research Laboratory; ³National MagLab; ⁴Qorvo, Inc.

Why did they need the MagLab?

The MagLab's 45T magnet was essential to fully explore the quantum hall states in the nitride semiconductor prior to exploring the region in which they coexist with superconductivity.

Details for scientists

View or download the expert-level Science Highlight, Quantum Rivals in Nitride Materials
Read the full-length publication, An all-epitaxial nitride heterostructure with concurrent quantum Hall effect and superconductivity, in Science Advances.

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1644779); D. Jena (NSF EFMA-1741694); C.S. Chang (NSF DMR-1539918 and MRSEC DMR-1719875); P. Dang (NSF DGE-1650441)

For more information, please contact Tim Murphy.