Topological Semimetal Pt3Sn: From Lab Thin Films to CHIPS Act-Backed Low-Energy Spintronic Memory

Topological Semimetal Pt3Sn Changes How We Build Computer Memory

Estimated reading time: 12 minutes

Key Takeaways

• The material is called topological semimetal Pt3Sn — a thin film of platinum and tin with a twist.
• The researchers used a manufacturing process that is already compatible with real-world chip production.
• The University of Minnesota team successfully created a thin film of Pt3Sn using sputtering.
• Pt3Sn and Pt3SnxFe1-x showed SOT efficiencies competitive with or superior to conventional heavy metals like platinum.
• A 2025 study published in Advanced Materials showed field-free perpendicular magnetization switching at room temperature.

The Tiny Material That Could Reshape Every Device You Own

Every phone call you make, every video you stream, every search you run — all of it burns energy. Most of that energy goes to waste inside chips that were designed decades ago using the same basic physics. Now, researchers at the University of Minnesota have created something that challenges the foundation of how computer chips store and process data.

The material is called topological semimetal Pt3Sn — a thin film of platinum and tin with a twist. Its electrons do not behave like electrons in normal metals or insulators. They follow quantum rules that give the material strange and useful properties. Properties that could make future computer chips faster, smaller, and dramatically less hungry for power.

This is not a distant dream. The researchers used a manufacturing process that is already compatible with real-world chip production. That means the path from lab to factory floor is shorter than almost any other next-generation material in development right now.

Here is what you need to know.

What Is a Topological Semimetal and Why Should You Care

Low-Energy Spintronics Starts With Understanding the Basics

Most computer chips today are built from traditional semiconductors — materials like silicon that control electrical current by switching it on and off. This system works, but it has a ceiling. As chips get smaller, squeezing more performance out of conventional silicon gets harder, and the heat and energy costs climb.

Topological semimetals are a different category of material entirely. They belong to a group called quantum materials, and the electrons inside them behave according to topology — a branch of mathematics that deals with properties that stay the same even when a shape is stretched or bent.

In practical terms, this means:

• Electrons in topological semimetals travel along the surface of the material in protected pathways
• These pathways are extremely resistant to interference and energy loss
• The materials show unusual responses to magnetic fields that standard metals do not

The specific material studied by the University of Minnesota team is Pt3Sn — a compound of platinum (Pt) and tin (Sn). When iron is added to the mix to create Pt3SnxFe1-x, the material’s magnetic properties can be tuned further, opening up a wider range of applications.

What makes topological semimetals especially exciting for computing is their connection to spintronics — a field that uses the spin of electrons, not just their charge, to store and process data. Traditional chips move electrons around to represent ones and zeros. Spintronic devices can flip the magnetic orientation of a tiny region of material to store data, and they can do it with far less energy.

spintronics

What the University of Minnesota Team Actually Did

Spin–Orbit Torque Memory Gets a Manufacturable Building Block

Before this study, topological semimetals had mostly been studied as bulk crystals — chunks of material grown under very specific laboratory conditions. That is interesting for physics, but it is not useful for making real chips. Chips are built using thin films: ultra-thin layers of material deposited onto a substrate in a controlled process.

The University of Minnesota team did something no one had done before. They successfully created a thin film of Pt3Sn using a process called sputtering — a standard industrial technique where atoms are knocked off a target material and deposited onto a surface. Critically, their sputtering process is already compatible with existing semiconductor manufacturing equipment.

This is a big deal. Many promising lab materials fail at the manufacturing stage because they require exotic tools or conditions that factories do not have. Pt3Sn was made using processes that chip manufacturers already use every day.

The study, published in Nature Communications in July 2023, reported two standout findings:

1. Negative Longitudinal Magnetoresistance

Normally, when you apply a magnetic field to a metal, the resistance in the material goes up. In Pt3Sn, the opposite happens — resistance goes down. The team had predicted this theoretically and confirmed it through measurement. This “negative longitudinal magnetoresistance” is a signature of topological behaviour and is directly linked to the material’s quantum properties.

2. Large Spin–Orbit Torque Efficiency

Spin–orbit torque (SOT) is the mechanism that lets a material switch the magnetic direction of a nearby layer with a tiny pulse of current. The higher the SOT efficiency, the less energy you need to flip that magnetic state — and the faster you can do it. Pt3Sn and Pt3SnxFe1-x showed SOT efficiencies competitive with or superior to conventional heavy metals like platinum that are currently used in the best spintronic devices.

Put simply: this material can switch magnetic memory states faster and with less energy than what we use today.

Nature Communications

Beyond the First Paper — What Has Happened Since

CHIPS Act Semiconductor R&D Puts Pt3Sn on the Strategic Map

The Nature Communications paper was the starting point. Subsequent research has pushed Pt3Sn further and confirmed that its early promise is holding up under closer examination.

Field-Free Switching at Room Temperature

One of the biggest practical challenges in spintronic memory is that many SOT switching demonstrations require an external magnetic field to work. That is not practical for real devices — you cannot build a field-generating magnet into every memory cell on a chip.

A 2025 study published in Advanced Materials showed that an ultrathin Pt3Sn layer with topological surface states can achieve field-free perpendicular magnetization switching at room temperature. That means the material can flip a magnetic bit without any external magnetic field assist, using only an electrical pulse. This removes one of the last major barriers between Pt3Sn and practical spintronic memory.

Advanced Materials

Bilinear Magnetoelectric Resistance — a New Tunable Channel

A 2024 study examined a different transport property in sputtered Pt3Sn called bilinear magnetoelectric resistance (BMER). The BMER values measured reached approximately 0.0034 nm² A⁻¹ Oe⁻¹ at room temperature.

This might sound like a dry number, but what it means is significant. BMER represents an additional way to read out and control the material’s magnetic state using electrical signals. In future chip designs, this could be used to build multi-functional sensing and logic elements — devices that can both store data and perform logical operations in the same physical layer, cutting down on the complexity and energy cost of separating memory and logic.

bilinear magnetoelectric resistance (BMER)

Why This Matters at a National Level

The United States has made semiconductor independence a policy priority. The CHIPS and Science Act of 2022 allocated roughly $52 billion to semiconductor incentives and research — approximately $39 billion for fab construction and about $11 billion for research programs. Within that, CHIPS for America programs under NIST have outlined up to around $300 million in awards for materials, substrates, and advanced packaging research, with individual awards potentially reaching $100 million each.

The research programs co-funding this work — SRC’s nCORE/SMART center and JUMP/ASCENT (co-sponsored with DARPA) — have published targets framing topological materials as capable of enabling up to 1,000 times improvement in energy-delay product compared to current CMOS technology. That is not a modest improvement. That is an order-of-magnitude shift in what computers can do per unit of energy consumed.

Pt3Sn, as a sputtered, industry-compatible topological semimetal, sits squarely in the centre of this roadmap.

NIST CHIPS

NIST outlines 300 million CHIPS Act awards

nCORE/SMART

JUMP/ASCENT

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The Physics That Makes It All Work

How Spin–Orbit Torque Memory Operates at the Quantum Level

To understand why Pt3Sn performs the way it does, it helps to look at the physics underneath.

Topology and Protected Surface States

In topological materials, the surface of the material hosts special electronic states that are protected by the material’s underlying quantum mechanical symmetry. Electrons in these surface states cannot easily scatter backwards — they keep moving forward regardless of most types of interference. This is why topological materials tend to have low electrical resistance at their surfaces even when the bulk has different properties.

In Pt3Sn, the transition from a weak topological insulator to a topological semimetal is achieved through magnetic doping — adding iron atoms to the crystal structure. This was the key innovation demonstrated by the University of Minnesota team. By controlling how much iron is added, the researchers can tune the material’s electronic properties, adjusting the strength of its topological surface states and its spin–orbit coupling.

Spin–Orbit Coupling and Torque

Spin–orbit coupling is the quantum mechanical interaction between an electron’s spin (its intrinsic magnetic moment) and its orbital motion around atomic nuclei. In heavy elements like platinum, this coupling is very strong, which is why platinum-based materials are already used in spintronic devices.

Pt3Sn takes this further. The topological surface states concentrate electrons at the material’s interface, where they experience particularly strong spin–orbit coupling. When a current flows through the material, this coupling generates a torque on the magnetic moments of atoms in an adjacent magnetic layer. That torque can flip the magnetic direction — writing a bit of data — with a small, precise, and fast electrical pulse.

Negative Magnetoresistance Explained

Senior author Tony Low’s team predicted — and the experiments confirmed — that applying a magnetic field along the current direction in Pt3Sn decreases rather than increases resistance. This negative longitudinal magnetoresistance is tied to a quantum phenomenon called the chiral anomaly — a property specific to Weyl and Dirac semimetals where applying parallel electric and magnetic fields causes an imbalance of electrons between different chirality nodes, reducing scattering and lowering resistance.

The fact that the team could observe this in a sputtered thin film, not just a bulk crystal, confirms that the topological properties survive the manufacturing process — a critical requirement for any real-world application.

negative longitudinal magnetoresistance

University of Minnesota

What This Means for the Future of Computing

The Road From Lab Thin Films to Real Spintronic Devices

It is worth being clear about where Pt3Sn sits on the timeline right now. This is foundational research — the kind that typically takes 10 to 20 years to reach consumer products. But several factors are compressing that timeline in this case.

Industry Compatibility Is Already There

Most promising lab materials hit a wall at scale-up. The sputtering technique used for Pt3Sn avoids this. It is the same class of deposition process used in chip fabs today. That means a company investigating this material does not need to build entirely new tooling — they need to adapt existing tooling, which is a much shorter and cheaper path.

The Right Properties Are Already Demonstrated

For a spintronic memory device to be commercially viable, it needs to show:

• Efficient magnetization switching with low current ✅
• Room-temperature operation ✅
• Field-free switching capability ✅
• Manufacturability ✅
• Tunable properties ✅

Pt3Sn has now demonstrated all five of these in peer-reviewed work. That is not common for emerging materials at this stage.

The Competition It Is Meant to Replace

The leading non-volatile memory technology today is STT-MRAM (spin-transfer torque magnetic RAM), already used in embedded applications by companies like Everspin and integrated into processors by Intel and Samsung. STT-MRAM is energy-efficient compared to DRAM and flash, but it still requires relatively high write currents and has switching speed limitations.

SOT-MRAM using materials like Pt3Sn could offer faster switching speeds and lower write energy, while maintaining the non-volatile storage advantage — data is retained even when the power is off. Industry analysts and the SRC roadmap documents frame this as the next generation of embedded and standalone memory, particularly for AI accelerators and edge computing devices where energy efficiency is the defining bottleneck.

SRC roadmap documents

Defense and National Security Applications

DARPA’s co-sponsorship of the JUMP/ASCENT program that supported this research is not coincidental. Low-power, high-speed, radiation-tolerant memory is a priority for military electronics — from satellite systems to autonomous vehicles and battlefield computing. Topological materials like Pt3Sn are inherently more resistant to certain types of electronic interference because their surface states are quantum-mechanically protected. This makes them attractive for applications where reliability under hostile conditions matters as much as raw performance.

JUMP/ASCENT

The Team and the Work Behind the Work

CHIPS Act Semiconductor R&D Depends on Interdisciplinary Teams

One detail worth highlighting is how this research was structured. Senior authors Jian-Ping Wang, Andre Mkhoyan, and Tony Low represent three different departments at the University of Minnesota — Electrical and Computer Engineering, Chemical Engineering and Materials Science, and Electrical and Computer Engineering (theory). They have been collaborating on topological materials for over a decade.

Wang brought expertise in device fabrication and spintronic systems. Mkhoyan specialised in material growth and detailed atomic-scale characterisation. Low provided the theoretical and computational framework to predict what the material would do before the experiments confirmed it.

This division of roles is important because it reflects how all cutting-edge materials research now works. No single researcher or single department can own every piece of the problem. The theory has to guide the growth, the growth has to enable the characterisation, and the characterisation has to feed back into the theory.

The full team included researchers from four University of Minnesota departments plus the University of Minnesota Characterization Facility — a shared equipment resource that provides the electron microscopy and spectroscopy tools needed to examine materials at the atomic scale.

Funding came from multiple government programs:

• nCORE/SMART — a Semiconductor Research Corporation center sponsored by NIST
• JUMP/ASCENT — a DARPA and MARCO co-sponsored program
• NSF MRSEC — under award DMR-2011401
• Minnesota Nano Center — supported by NSF NNCI under award ECCS-2025124

This level of multi-agency, multi-department coordination is exactly the model that the CHIPS and Science Act is designed to scale up across the United States.

nCORE/SMART

CHIPS for America

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