{"id":129903,"date":"2025-05-25T05:48:08","date_gmt":"2025-05-25T05:48:08","guid":{"rendered":"https:\/\/www.europesays.com\/uk\/129903\/"},"modified":"2025-05-25T05:48:08","modified_gmt":"2025-05-25T05:48:08","slug":"scientists-discover-one-of-the-worlds-thinnest-semiconductor-junctions-forming-inside-a-quantum-material","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/uk\/129903\/","title":{"rendered":"Scientists discover one of the world’s thinnest semiconductor junctions forming inside a quantum material"},"content":{"rendered":"

\"Scientists<\/p>\n

Equilibrium band structure of Mn(Bi1\u2212xSbx)6Te10 with x = 0.18. (a) Band structures along the \u0393\u2013M direction on the MBT and 1-BT terminations. (b) Hall measurements for 18% Sb-doped MnBi6Te10 at 5 K showing the carrier density \u223c6.5 \u00d7 1018 cm\u22123, near the charge-neutral point. (c) Illustrations of different cleaved terminations in MnBi6Te10 and sketches of their band structures. Credit: Nanoscale (2025). DOI: 10.1039\/D4NR04812A<\/p>\n

Scientists studying a promising quantum material have stumbled upon a surprise: within its crystal structure, the material naturally forms one of the world’s thinnest semiconductor junctions\u2014a building block of most modern electronics. The junction is just 3.3 nanometers thick, about 25,000 times thinner than a sheet of paper.<\/p>\n

“This was a big surprise,” said Asst. Prof. Shuolong Yang. “We weren’t trying to make this junction, but the material made one on its own, and it’s one of the thinnest we’ve ever seen.”<\/p>\n

The discovery offers a way to build ultra-miniaturized electronic components, and also provides insight into how electrons behave in materials designed for quantum applications.<\/p>\n

The paper, titled “Spectroscopic evidence of intra-unit-cell charge redistribution in a charge-neutral magnetic topological insulator,” is published<\/a> in the journal Nanoscale.<\/p>\n

Uneven electrons<\/p>\n

Researchers at the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) and Pennsylvania State University were studying the electronic properties of MnBi\u2086Te\u2081\u2080, a type of topological substance known for its unusual properties\u2014like letting electricity flow freely along its edges without any resistance. Scientists hope that this class of topological material could someday be used in quantum computers or ultra-efficient electronic devices.<\/p>\n

But to work properly, materials like MnBi\u2086Te\u2081\u2080 need to have carefully balanced and distributed electrons. The team thought they had achieved the right balance by tweaking the material’s chemical makeup and infusing MnBi\u2086Te\u2081\u2080 with antimony. Regular electrical tests confirmed the material was, overall, neutral.<\/p>\n

Then Yang’s team looked closer, using a technique called time- and angle-resolved photoemission spectroscopy<\/a> (trARPES) that uses ultrafast laser pulses to observe how electrons are distributed and how their energy levels<\/a> shift in real time. The scientists saw something unexpected. Within each repeating layer of the crystal\u2014just a few atoms thick\u2014the electrons were not evenly spread. Instead, they were clumping up in some parts and leaving other parts with fewer electrons. This created tiny built-in electric fields within the material.<\/p>\n

\"Scientists<\/p>\n

Researchers at the University of Chicago Pritzker School of Molecular Engineering, including Asst. Prof. Shuolong Yang (left) and graduate student Khanh Duy Nguyen, have discovered one of the world’s thinnest semiconductor junctions naturally forming within a promising quantum material. Credit: John Zich<\/p>\n

“In an ideal quantum material, you want a really uniform distribution of charges,” said UChicago PME graduate student Khanh Duy Nguyen, the first author of the new work. “Seeing this uneven distribution suggests that we may not enable quantum applications in the originally planned fashion, but reveals this other really useful phenomenon.”<\/p>\n

These tiny regions acted like p-n junctions, a type of semiconductor junction that contains internal electric fields and is used to build diodes\u2014similar to the ones found in everyday electronics like phones and computers. But unlike manufactured p-n junctions, these ones form naturally as part of the crystal itself.<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tA boon for quantum and electronic applications<\/p>\n

Because the new, naturally forming p-n junction is also highly responsive to light, it could be useful for next-generation electronics, including spintronics\u2014a type of technology that stores and manipulates data using an electron’s magnetic spin rather than its charge.<\/p>\n

By modeling what was occurring within the crystal structure<\/a> of MnBi\u2086Te\u2081\u2080, Nguyen, Yang and their colleagues were able to form a hypothesis about how it formed the p-n junctions. Introducing antimony into MnBi\u2086Te\u2081\u2080, they suspect, leads to swapping between manganese atoms and antimony, causing charge differences throughout the material.<\/p>\n

While the finding adds complexity to efforts to use the material for certain types of quantum effects, it opens up new applications in electronics. It also paves the way toward further engineering of MnBi\u2086Te\u2081\u2080 so that it does maintain evenly distributed electrons\u2014and can be useful in quantum engineering.<\/p>\n

The UChicago PME team is fine-tuning ways of fabricating thin films of the material\u2014rather than large, three-dimensional crystals. This could let them more precisely control the behavior of electrons, either to boost quantum properties, or to boost the yield of tiny p-n junctions.<\/p>\n

“This once again demonstrates the value of pursuing basic, fundamental scientific research and being open about where it leads,” said Yang. “We set out with one goal and found a surprise that led us in another, really exciting direction.”<\/p>\n

More information:<\/strong>
\n\t\t\t\t\t\t\t\t\t\t\t\tKhanh Duy Nguyen et al, Spectroscopic evidence of intra-unit-cell charge redistribution in a charge-neutral magnetic topological insulator, Nanoscale (2025). DOI: 10.1039\/D4NR04812A<\/a><\/p>\n

\n\t\t\t\t\t\t\t\t\t\t\t\t\tProvided by
\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tUniversity of Chicago<\/a>
\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/p>\n

\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/p>\n

\n\t\t\t\t\t\t\t\t\t\t\t\tCitation<\/strong>:
\n\t\t\t\t\t\t\t\t\t\t\t\tScientists discover one of the world’s thinnest semiconductor junctions forming inside a quantum material (2025, May 20)
\n\t\t\t\t\t\t\t\t\t\t\t\tretrieved 25 May 2025
\n\t\t\t\t\t\t\t\t\t\t\t\tfrom https:\/\/phys.org\/news\/2025-05-scientists-world-thinnest-semiconductor-junctions.html\n\t\t\t\t\t\t\t\t\t\t\t <\/p>\n

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