Sadly the study itself is paywalled so I couldn’t go too deep into it but reading some other articles and also some other news articles covering this study, the way I understand it is so:

Heat buildup in electronics cause a reduction in performance, and is a direct result of electricity flowing through the electronic circuits. Therefore it is unavoidable (at least until we achieve room temp superconductors - which conduct electricity without causing heat build up).

So far we have relied on passive heat flow to keep electronic circuits under their max operating temperature. For example, a heat sink attached directly to critical locations of heat build up in the circuit. In this example, the heat cant be controlled, it is always flowing into the heat sink.

When the circuit is first activated the heat sink is at room temp and can conduct heat out of the circuit at a high rate. However, the sink has a maximum rate of heat dissipation, so once the sink heats up, the rate of heat flowing out of the circuit and into the sink is decreased, which limits the circuits performance.

Think of it like a kitchen sink. The tap can blast water into the sink at a high rate but the drain cant drain the water at the same rate, so once the sink is full, you have to turn down the flow of water from the tap. The tap is the flow of heat from the circuit into the heat sink, and the drain is the heat dissipating from the heat sink.

Apparently, this new device will form a critical part of a different, more controlled method of heat dissipation.

The way I understand it, you could perhaps have 2 heat sinks with the device directing the flow of heat to only one sink at a time. When the first heat sink reaches critical capacity, instead of reducing the performance of the circuit to reduce heat production, the new device can efficiently and rapidly switch the flow of heat into the second heat sink, which has been inactive up until this point.

The first heat sink no longer has heat flowing into it and can cool down rapidly, while the newly active heat sink can conduct heat out of the circuit at peak performance until it reaches capacity.

At which point, presumably, the new device from the study would switch the heat flow again, back into the first heat sink, which can perform maximally once more as it has theoretically returned to room temp.

To use the kitchen sink analogy, it would be like having two kitchen sinks, and the newly created device allows you to switch the tap to the second sink once the first is full without decreasing the flow out of the tap. The first sink then has time to drain without any further water input while the second sink can handle the full output of the tap.