Strain-tunable metamagnetic critical endpoint in Mott insulating rare-earth titanates

Article

关键词: TOTAL-ENERGY CALCULATIONS;    QUANTUM CRITICALITY;    MAGNETIC-PROPERTIES;    WIDOM LINE;    LIQUID;    TRANSITION;    OXIDES;    CROSSOVER;    DYNAMICS;    BEHAVIOR;   

DOI  :  10.1103/PhysRevB.105.144404

来源: SCIE

【 摘 要 】

Rare-earth titanates are Mott insulators whose magnetic ground state???antiferromagnetic (AFM) or ferromagnetic (FM)???can be tuned by the radius of the rare-earth element. Here, we combine phenomenology and first-principles calculations to shed light on the generic magnetic phase diagram of a chemically substituted titanate on the rare-earth site that interpolates between an AFM and a FM state. Octahedral rotations present in these perovskites cause the AFM order to acquire a small FM component???and vice-versa???removing any multicritical point from the phase diagram. However, for a wide parameter range, a first-order metamagnetic transition line terminating at a critical endpoint survives inside the magnetically ordered phase. Like the liquidgas transition, a Widom line emerges from the endpoint, characterized by enhanced fluctuations. In contrast to metallic FMs, this metamagnetic transition involves two symmetry-equivalent and insulating canted spin states. Moreover, instead of a magnetic field, we show that uniaxial strain can be used to tune this transition to zero temperature, inducing a quantum critical endpoint.

【 授权许可】

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