Distinctive quantum materials may allow ultra-powerful, compact computer systems

Data in computer systems is transmitted by means of semiconductors by the motion of electrons and saved within the course of the electron spin in magnetic supplies. To shrink gadgets whereas bettering their efficiency—a objective of an rising discipline known as spin-electronics (“spintronics”)—researchers are looking for distinctive supplies that mix each quantum properties. Writing in Nature Supplies, a crew of chemists and physicists at Columbia finds a powerful hyperlink between electron transport and magnetism in a cloth known as chromium sulfide bromide (CrSBr). 

Created within the lab of Chemist Xavier Roy, CrSBr is a so-called van der Waals crystal that may be peeled into stackable, 2D layers which can be just some atoms skinny. Not like associated supplies which can be shortly destroyed by oxygen and water, CrSBr crystals are secure at ambient circumstances. These crystals additionally keep their magnetic properties on the comparatively excessive temperature of -280F, avoiding the necessity for costly liquid helium cooled to a temperature of -450F, 

“CrSBr is infinitely simpler to work with than different 2D magnets, which lets us fabricate novel gadgets and check their properties,” stated Evan Telford, a postdoc within the Roy lab who graduated with a PhD in physics from Columbia in 2020. Final yr, colleagues Nathan Wilson and Xiaodong Xu on the College of Washington and Xiaoyang Zhu at Columbia discovered a hyperlink between magnetism and the way CrSBr responds to gentle. Within the present work, Telford led the trouble to discover its digital properties.

The crew used an electrical discipline to check CrSBr layers throughout completely different electron densities, magnetic fields, and temperatures—completely different parameters that may be adjusted to supply completely different results in a cloth. As digital properties in CrSBr modified, so did its magnetism. 

“Semiconductors have tunable digital properties. Magnets have tunable spin configurations. In CrSBr, these two knobs are mixed,” stated Roy. “That makes CrSBr engaging for each elementary analysis and for potential spintronics software.”

Magnetism is a tough property to measure straight, notably as the scale of the fabric shrinks, defined Telford, but it surely’s straightforward to measure how electrons transfer with a parameter known as resistance. In CrSBr, resistance can function a proxy for in any other case unobservable magnetic states. “That is very {powerful},” stated Roy,  particularly as researchers look to sooner or later construct chips out of such 2D magnets, which might be used for quantum computing and to retailer huge quantities of knowledge in a small area.

The hyperlink between the fabric’s digital and magnetic properties was because of defects within the layers—for the crew, a fortunate break, stated Telford. “Folks normally need the ‘cleanest’ materials doable. Our crystals had defects, however with out these, we would not have noticed this coupling,” he stated. 

From right here, the Roy lab is experimenting with methods to develop peelable van der Waals crystals with deliberate defects, to enhance the flexibility to fine-tune the fabric’s properties. They’re additionally exploring whether or not completely different combos of components may perform at larger temperatures whereas nonetheless retaining these useful mixed properties.