Wednesday, February 21, 2024

Uniting Twistronics and Spintronics for Superior Electronics

Spintronics Computing Art

Twistronics, a novel subject in quantum physics, includes stacking van der Waals supplies to discover new quantum phenomena. Researchers at Purdue College have superior this subject by introducing quantum spin into twisted double bilayers of antiferromagnets, resulting in tunable moiré magnetism. This breakthrough suggests new supplies for spintronics and guarantees developments in reminiscence and spin-logic gadgets. Credit score:

Purdue quantum researchers twist double bilayers of an antiferromagnet to exhibit tunable moiré magnetism.

Twistronics isn’t a brand new dance transfer, train gear, or new music fad. No, it’s a lot cooler than any of that. It’s an thrilling new growth in quantum physics and materials science the place van der Waals supplies are stacked on prime of one another in layers, like sheets of paper in a ream that may simply twist and rotate whereas remaining flat, and quantum physicists have used these stacks to find intriguing quantum phenomena.

Including the idea of quantum spin with twisted double bilayers of an antiferromagnet, it’s potential to have tunable moiré magnetism. This implies a brand new class of fabric platform for the subsequent step in twistronics: spintronics. This new science might result in promising reminiscence and spin-logic gadgets, opening the world of physics as much as a complete new avenue with spintronic functions.

Combining Twistronics With Spintronics

By twisting a van der Waals magnet, non-collinear magnetic states can emerge with vital electrical tunability. Credit score: Ryan Allen, Second Bay Studios

A workforce of quantum physics and supplies researchers at Purdue College has launched the twist to manage the spin diploma of freedom, utilizing CrI3, an interlayer-antiferromagnetic-coupled van der Waals (vdW) materials, as their medium. They’ve revealed their findings, “Electrically tunable moiré magnetism in twisted double bilayers of chromium triiodide,” in Nature Electronics.

“On this examine, we fabricated twisted double bilayer CrI3, that’s, bilayer plus bilayer with a twist angle between them,” says Dr. Guanghui Cheng, co-lead creator of the publication. “We report moiré magnetism with wealthy magnetic phases and vital tunability by {the electrical} technique.”

Moiré Superlattice Structure of Twisted Double Bilayer CrI3

The moiré superlattice construction of twisted double bilayer (tDB) CrI3 and its magnetic behaviors probed by the magneto-optical-Kerr-effect (MOKE). Part a above exhibits the schematic of moiré superlattice fabricated by interlayer twisting. Backside panel: a non-collinear magnetic state can emerge. Part b above exhibits MOKE outcomes present the coexistence of antiferromagnetic (AFM) and ferromagnetic (FM) orders within the “moiré magnet” tDB CrI3 in contrast with the AFM orders in pure antiferromagnetic bilayer CrI3. Credit score: Illustration by Guanghui Cheng and Yong P. Chen

“We stacked and twisted an antiferromagnet onto itself and voila obtained a ferromagnet,” says Chen. “That is additionally a putting instance of the not too long ago emerged space of ‘twisted’ or moiré magnetism in twisted 2D supplies, the place the twisting angle between the 2 layers offers a strong tuning knob and modifications the fabric property dramatically.”

“To manufacture twisted double bilayer CrI3, we tear up one a part of bilayer CrI3, rotate and stack onto the opposite half, utilizing the so-called tear-and-stack method,” explains Cheng. “By magneto-optical Kerr impact (MOKE) measurement, which is a delicate device to probe magnetic conduct down to some atomic layers, we noticed the coexistence of ferromagnetic and antiferromagnetic orders, which is the hallmark of moiré magnetism, and additional demonstrated voltage-assisted magnetic switching. Such a moiré magnetism is a novel type of magnetism that includes spatially various ferromagnetic and antiferromagnetic phases, alternating periodically in response to the moiré superlattice.”

Twistronics up up to now have primarily targeted on modulating digital properties, akin to twisted bilayer graphene. The Purdue workforce needed to introduce the twist to spin diploma of freedom and selected to make use of CrI3, an interlayer-antiferromagnetic-coupled vdW materials. The results of stacked antiferromagnets twisting onto itself was made potential by having fabricated samples with completely different twisting angles. In different phrases, as soon as fabricated, the twist angle of every system turns into fastened, after which MOKE measurements are carried out.

Theoretical calculations for this experiment have been carried out by Upadhyaya and his workforce. This supplied robust help for the observations arrived at by Chen’s workforce.

“Our theoretical calculations have revealed a wealthy section diagram with non-collinear phases of TA-1DW, TA-2DW, TS-2DW, TS-4DW, and so forth.,” says Upadhyaya.

This analysis folds into an ongoing analysis avenue by Chen’s workforce. This work follows a number of associated latest publications by the workforce associated to novel physics and properties of “2D magnets,” akin to “Emergence of electric-field-tunable interfacial ferromagnetism in 2D antiferromagnet heterostructures,” which was not too long ago revealed in Nature Communications. This analysis avenue has thrilling potentialities within the subject of twistronics and spintronics.

“The recognized moiré magnet suggests a brand new class of fabric platform for spintronics and magnetoelectronics,” says Chen. “The noticed voltage-assisted magnetic switching and magnetoelectric impact might result in promising reminiscence and spin-logic gadgets. As a novel diploma of freedom, the twist might be relevant to the huge vary of homo/heterobilayers of vdW magnets, opening the chance to pursue new physics in addition to spintronic functions.”

Reference: “Electrically tunable moiré magnetism in twisted double bilayers of chromium triiodide” by Guanghui Cheng, Mohammad Mushfiqur Rahman, Andres Llacsahuanga Allcca, Avinash Rustagi, Xingtao Liu, Lina Liu, Lei Fu, Yanglin Zhu, Zhiqiang Mao, Kenji Watanabe, Takashi Taniguchi, Pramey Upadhyaya and Yong P. Chen, 19 June 2023, Nature Electronics.
DOI: 10.1038/s41928-023-00978-0

The workforce, principally from Purdue, has two equal-contributing lead authors: Dr. Guanghui Cheng and Mohammad Mushfiqur Rahman. Cheng was a postdoc in Dr. Yong P. Chen’s group at Purdue College and is now an Assistant Professor in Superior Institute for Materials Analysis (AIMR, the place Chen can be affiliated as a principal investigator) at Tohoku College. Mohammad Mushfiqur Rahman is a PhD scholar in Dr. Pramey Upadhyaya’s group. Each Chen and Upadhyaya are corresponding authors of this publication and are professors at Purdue College. Chen is the Karl Lark-Horovitz Professor of Physics and Astronomy, a Professor of Electrical and Pc Engineering, and the Director of Purdue Quantum Science and Engineering Institute. Upadhyaya is an Assistant Professor of Electrical and Pc Engineering. Different Purdue-affiliated workforce members embrace Andres Llacsahuanga Allcca (PhD scholar), Dr. Lina Liu (postdoc), and Dr. Lei Fu (postdoc) from Chen’s group, Dr. Avinash Rustagi (postdoc) from Upadhyaya’s group and Dr. Xingtao Liu (former analysis assistant at Birck Nanotechnology Heart).

This work is partially supported by US Division of Power (DOE) Workplace of Science by means of the Quantum Science Heart (QSC, a Nationwide Quantum Info Science Analysis Heart) and Division of Protection (DOD) Multidisciplinary College Analysis Initiatives (MURI) program (FA9550-20-1-0322). Cheng and Chen additionally acquired partial help from WPI-AIMR, JSPS KAKENHI Fundamental Science A (18H03858), New Science (18H04473 and 20H04623), and Tohoku College FRiD program in early levels of the analysis.

Upadhyaya additionally acknowledges help from the Nationwide Science Basis (NSF) (ECCS-1810494). Bulk CrI3 crystals are supplied by the group of Zhiqiang Mao from Pennsylvania State College below the help of the US DOE (DE-SC0019068). Bulk hBN crystals are supplied by Kenji Watanabe and Takashi Taniguchi from Nationwide Institute for Supplies Science in Japan below help from the JSPS KAKENHI (Grant Numbers 20H00354, 21H05233 and 23H02052) and World Premier Worldwide Analysis Heart Initiative (WPI), MEXT, Japan.

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