Topological Materials

Introduction of Topological materials

TopoLogic Inc., the University of Tokyo's first startup company, is working on Topological Materials that, due to the uniqueness of their band structure, exhibit two macro effects: the "anomalous Nernst effect (ANE)" and the "anomalous Hall effect (AHE)." These enable devices with new characteristics.
With the anomalous Nernst effect, it is possible to realize a thin and simple thermal flow sensor. This opens the door to applications such as biometric sensors capable of detecting thermal comfort, abnormal detection in batteries or semiconductors, predictive monitoring of manufacturing equipment failures, heat leakage detection, insulation detection, and thermoelectric devices.
On the other hand, the anomalous Hall effect can achieve ultra-fast magnetic memory. This has promising applications for embedded first-level cache memory, low-power memory for IoT devices, and non-volatile logic devices.
Tehno Alpha will promote advocacy and projectization of the company's topological materials in collaboration with TopoLogic Inc. The business model consists of selling or licensing the company's intellectual property.

Fig. Business model scheme

What is “topological materials？

Topological materials are substances with unprecedented electron structures that were awarded the Nobel Prize in Physics in 2016. In the past, similar discoveries have been made in the realm of semiconductors. Topological materials derive their name from their topological features (topology) within the electron bands, which include singular points such as Weyl points and Dirac points. These singular points give rise to highly potent virtual magnetic fields (microscopic magnetic fields) and induce unique electron flow within the material. As a result, they exhibit various electromagnetic properties unlike those found in other materials.
The main macroscopic effects stemming from the band structure of topological materials are the anomalous Nernst effect and the anomalous Hall effect. These effects are a consequence of the influence of the virtual magnetic field in topological materials and are particularly characteristic of them. These effects are not observed in existing materials, allowing for the realization of devices and electronic components with entirely novel structures.
One of these distinctive macroscopic effects, the anomalous Nernst effect, is a type of thermoelectric effect where a voltage is generated in response to a temperature gradient within a material. A similar thermoelectric effect known as the Seebeck effect is commonly recognized, but while the Seebeck effect generates a voltage potential in the same direction as the temperature gradient, the anomalous Nernst effect generates a voltage potential perpendicular to the temperature gradient. Conventional thermoelectric materials faced challenges such as complex structures, limited thinness, and high costs due to the voltage differential aligning with the temperature gradient. In contrast, utilizing the anomalous Nernst effect in thermoelectric devices allows for the design of highly versatile thermoelectric devices, as the direction of the temperature gradient and voltage potential differ.

Quotation: JST CREST New Technology Presentation "Innovative Thermoelectric Conversion Technology Using Magnetic Materials and Its Applications in Thermoelectric Modules and Heat Flow Sensors" March 8th, 2019

What is TopoLogic Inc.？

TopoLogic Inc. was founded in July 2021 as a quantum materials startup originating from the research group of Professor Tomo Tsujii in the Department of Physics at the University of Tokyo. The company aims to implement and bring to society new devices based on "topological materials" researched and developed by the group.
TopoLogic focuses on the lateral thermoelectric conversion effect and spintronics based on novel orders, striving to achieve the development of devices that were previously challenging to realize.

Fig. Awards / Selections records

Device ＆ Applications

Heat Flux Sensor “TL-Sensing™

Our heat flux sensor “TL-Sensing™” detects temperature gradients (i.e., heat flux) within a material by generating a proportional voltage potential, which can be read as an electrical signal. Unlike conventional Seebeck-type heat flux sensors, this type of sensor can achieve an extremely thin thickness (as thin as 100nm) and can capture significant temperature gradients even with minimal temperature differences (e.g., 0.1℃), making it highly detectable. Furthermore, due to the sensor's thinness, its thermal capacity is remarkably small, enabling rapid response to changes in heat flow, such as within 0.1 seconds.
Additionally, this sensor can be manufactured through traditional processes like sputtering, allowing for cost-effective production and easy integration into existing manufacturing lines. It offers economic advantages compared to conventional models (ranging from tens of thousands to a few hundred thousand yen). Furthermore, it can be deposited on a variety of substrates, including silicon, plastic, and film, without being restricted by substrate type.

For Temporary Use

To allow you to experience the fundamental characteristics such as response time and accuracy of our heat flux sensors, we offer a paid sample lending program for approximately 2 weeks. Please use this timeframe as a guideline. The basic specifications are provided below for your reference.
As the sensor provides analog output, when evaluating parameters like sensitivity, we recommend utilizing your existing data logger, measurement power source, oscilloscope, or similar equipment to assess and verify the sensor's performance.

If you're interested in participating in our sample lending program, kindly reach out to us for further details on availability, pricing, and terms. This program is designed to give you a hands-on understanding of our sensor technology's capabilities.

Applications of Heat Flux Detection

In the case of conventional Seebeck-type heat flux sensors, their high cost has limited their usage mainly to research and development applications. On the other hand, heat flux sensors based on topological materials exhibit exceptionally high sensitivity to heat flow (on the order of 0.001 seconds) due to the anomalous Nernst effect and the material's sub-micron thickness. This enables them to capture the dynamics of heat itself. Furthermore, the flexibility in sensor design and low cost contribute to a wide range of applications.
For instance, they can be used to visualize heat generation in manufacturing processes, detect abnormal heat generation, and predict and monitor failures based on heat. In the context of wearable devices, they can monitor heat dissipation (absorption) from the human or animal body, allowing for estimation of health conditions and comfort levels. These sensors can also be integrated into automotive and IoT devices, enabling diverse heat-related monitoring.
Additionally, by introducing substances that react with specific chemicals on the sensor's surface to generate reaction heat absorption, it's possible to detect various substances like gases or antigens. These sensors have the potential to detect heat absorption from various activities in the world, making them versatile tools for activity monitoring.

Chemical Sensors and Gas Sensors

By introducing a catalytic layer as a functional film onto the surface of the heat flux sensor element, it becomes possible to enhance reactions with specific substances, enabling the detection of heat flows resulting from these reactions. Leveraging this principle, for instance, by employing a platinum catalytic layer to promote the reaction with hydrogen, the sensor can detect the presence of hydrogen based on the resulting heat flow. Using the sensitivity of this type of heat flux sensor, it's also conceivable to detect hydrogen concentrations as low as a few parts per million (ppm). This capability allows for the detection of even minute hydrogen leaks from pipes or tanks in hydrogen plants and fuel-cell vehicles.
Moreover, by selecting an appropriate functional film, the application can extend beyond hydrogen detection. It becomes possible to detect various types of gases, such as ammonia or hydrocarbon gases. This versatility in gas detection is achievable by tailoring the catalytic layer to suit the specific gas of interest.

Optical Sensors

When light shines on a heat flux sensor (or an optical absorption film placed on its surface), the energy of the light is converted into heat. By detecting this heat with the heat flux sensor, the device can be functioned as a light-receiving element, essentially acting as an optical sensor. Leveraging the high-speed response of TL-Sensor™ heat flux sensors, light reception can be detected within an order of 0.01 seconds. This capability enables a more responsive feedback system compared to conventional light-receiving element-based systems.

High-speed Memory

At present, it may not be possible to provide specific application examples, but it holds the potential to realize promising memory technology in the future.

Pamphlet

Pamphlet of Topological materials