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The spin-1/2 nearest neighbour AFM Heisenberg model on square lattice is known to exhibit an exotic phase diagram depending on the J2/J1 strength. In this seminar, I will talk about a semi-classical approach which captures the effective quantum picture by using dimers as proxy for quantum fluctuations. In the final part I will show the changes in the same model on introducing vacancies/holes (spin 0). It is observed that the intermediate spin-liquid/dimer region between Néel order and collinear AFM state gets extended on both the sides.

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Anish Koley, IISER Mohali (India)
Seminar Room 0.03, ETP
Contact: Matteo Rizzi