# NTU reports first evidence of the orbital Nernst effect in YIG/Pt/CuOx heterostructures

- Published: 2026-11-13 22:18 UTC
- Section: Science › Physics
- Tags: orbital Nernst effect, orbitronics, orbital Hall effect, magneto-thermopower, YIG/Pt/CuOx, spin Nernst effect, heat-driven orbital current, National Taiwan University, oxidized copper, thermoelectric energy conversion
- URL: https://realtech.media/news/rt-13d3f09c23727efb833d4a1d_ntu_reports_first/

**Researchers at National Taiwan University measured magneto-thermopower in YIG/Pt/CuOx layers and found a heat-driven orbital current, which had not been observed experimentally before.**

![NTU reports first evidence of the orbital Nernst effect in YIG/Pt/CuOx heterostructures](https://realtech.media/media/2026/11/a8a902973a2f8209.png)
*nature.com*

Researchers at National Taiwan University have reported the first experimental evidence of the orbital Nernst effect: a transverse flow of orbital angular momentum driven by a temperature gradient. The work by Li et al., published in Nature Communications (2026) and available on nature.com, is based on measurements of magneto-thermopower in yttrium iron garnet (YIG)/Pt/CuOx heterostructures [1].

The orbital Hall effect, its electrical counterpart, has been studied extensively, but the thermal version had remained experimentally elusive [1]. The spin Nernst effect has been observed in heavy metals, topological insulators and alloys, whereas the orbital Nernst effect, predicted to be more significant, had been missing [1].

## Sample design and measurement

Naturally oxidized copper (CuOx) served as the source of orbital current. Earlier work showed that it produces substantial orbital currents with negligible spin current, and that orbital texture in it arises from local Cu-O hybridization rather than a well-defined interface [1]. In the experiment, heat flows along the sample, and the in-plane temperature difference drives accumulation of orbital angular momentum at the top and bottom surfaces of the CuOx film. This angular momentum diffuses into the platinum layer, where spin-orbit coupling converts it into a spin current [1].

The magnetic insulator YIG acts as a gate for that spin current. When the spins are parallel to the YIG magnetization, they are reflected back into Pt and produce an additional voltage through the inverse spin Hall effect. When the spins are perpendicular to the magnetization, they are absorbed by YIG and no extra voltage appears [1].

## Comparison with reference structures

Orbital and spin angular momentum are hard to tell apart because both share the same detection geometry, and heat flow is harder to control and characterize than electric current [1]. To separate the contributions, the team compared YIG/Pt/CuOx with YIG/Pt and YIG/CuOx structures. According to the authors, both the magneto-thermopower and the magnetoresistance in YIG/Pt/CuOx were markedly enhanced, owing to the orbital Nernst effect and the orbital Hall effect in CuOx, respectively [1].

The authors state that the result supports the orbital degree of freedom as a route for heat-energy harvesting and for thermal transport of orbital angular momentum in earth-abundant materials [1].

## Sources

1. [nature.com](https://www.nature.com/articles/s41467-026-77878-2)
2. [ResearchSEA](https://www.asiaresearchnews.com/node/23687)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-13d3f09c23727efb833d4a1d_ntu_reports_first/