The ground state of quantum spin liquid was observed for the first time

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Spin is the internal property of an electron related to rotation , It is spin that makes the material in the magnet magnetic . In some materials , Spin can cause structural disorder , Similar to molecules in liquids , So there is “ Spin liquid ” The idea that . The main characteristics of spin liquids are , Even if it cools to absolute zero ( Below zero 273 Centigrade ), They remain disordered , This is because as the material cools , The spin direction fluctuates continuously , Instead of stabilizing in a solid state like a traditional magnet ( In traditional magnets , All spins are aligned ).

The researchers explained that , Think of an electron as a little compass pointing up or down . In traditional magnets , The electron spins all point in the same direction , Up or down , Form what is called “ Ferromagnetic phase ”. But in quantum spin liquids , The electrons are placed in a triangular lattice , Form a triangle , It is characterized by strong turbulence that interferes with their order , The result is an entangled wave function , No magnetic sequence .

Head of the latest research 、 Andrea, Professor of physics at the University of Montreal · Bianchi explained :“ When adding a third electron , Electron spins cannot be aligned , Because the spins of two adjacent electrons are opposite , This produces what we call magnetoresistive frustration . And this ground state, which produces excitation , Even at very low temperatures , It can also maintain spin disorder , So as to maintain the liquid .”

Bianchi said ,Ce2Zr2O7 It is a kind of cerium based material with magnetism , Scientists have previously made this compound , The new research is to make it in a unique pure form , They used samples melted in an optical furnace to make almost complete beauty Triangular atomic arrangement , Then check the quantum state . It turns out that , It is this almost perfect triangle , Make them in Ce2Zr2O7 Magnetoresistive frustration is created in .

Ambich said :“ Our measurements show that , Particle function overlap , Therefore, there is no obvious sign of classical magnetic sequence . Besides , We also observe the distribution of continuous fluctuations in the spin direction , This is characteristic of spin liquids and magnetoresistance , This shows that the materials we create behave like real spin liquids at low temperatures .”

After confirming these observations by computer simulation , The team came to the conclusion that , They did observe an unprecedented quantum state —— Quantum spin liquid ground state .


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2022-05-14