Editing Thermal diode (section)

==One-way heat-flow==
A thermal diode in this sense is a device whose [[thermal resistance]] is different for heat flow in one direction than for heat flow in the other direction. I.e., when the thermal diode's first terminal is hotter than the second, heat will flow easily from the first to the second, but when the second terminal is hotter than the first, little heat will flow from the second to the first.

Such an effect was first observed in a [[copper]]–[[Cuprous oxide|cuprous-oxide]] interface by [[Chauncey Starr]] in the 1930s. Beginning in 2002, theoretical models were proposed to explain this effect. In 2006 the first microscopic solid-state thermal diodes were built.<ref>{{Cite journal|last1=Wang|first1=Lei|last2=Li|first2=Baoweng|date=March 2008|title=Phononics gets hot|journal=Physics World|volume=21|issue=3|pages=27–29|doi=10.1088/2058-7058/21/03/31|bibcode=2008PhyW...21c..27W}}</ref> In April 2015 Italian researchers at [[Consiglio Nazionale delle Ricerche|CNR]] announced development of a working thermal diode,<ref>https://www.cnr.it/it/comunicato-stampa/6045/ CNR - Diodo termico, dove il calore va a senso unico</ref> publishing results in [[Nature Nanotechnology]].<ref>{{Cite journal | doi=10.1038/nnano.2015.11|pmid = 25705868| title=Rectification of electronic heat current by a hybrid thermal diode| journal=Nature Nanotechnology| volume=10| issue=4| pages=303–307| year=2015| last1=Martínez-Pérez| first1=Maria José| last2=Fornieri| first2=Antonio| last3=Giazotto| first3=Francesco|arxiv = 1403.3052|bibcode = 2015NatNa..10..303M|s2cid = 11654721}}</ref>

[[Thermosiphon|Thermal siphons]] can act as a one-way heat flow. 
[[Heat pipe]]s operating in [https://www.1-act.com/resources/heat-pipe-fundamentals/different-types-of-heat-pipes/diode-heat-pipes/ gravity] may also have this effect.