论文标题
NQR和NMR光谱中的奇数多极材料Cecosi
NQR and NMR spectra in odd-parity multipole material CeCoSi
论文作者
论文摘要
我们从理论上研究了NQR和NMR光谱，该光谱是源自交错的抗铁磁和抗氟二核秩序的奇数多物。对于$ f $ - 电子金属，cecosi是托有奇数多物的候选者，我们得出了一个有效的高精细场，作用于从零和非零磁场下CE离子的电子起源多极矩产生的CO核。我们阐明，在没有全局反转对称性的情况下，通过有效的超精细耦合，新兴的奇数多物通过NQR和NMR中的Sublattice依赖性光谱分裂产生。我们主要在三个奇数多极有序状态下检查NQR和NMR光谱的行为：A $ y $ type磁性环形偶极子订单，带有交错的$ x $ x $ type的反铁磁结构，$ xy $ xy $ xy $ -xy $ -xy $ -xy $ -xy type type turoidal toroidal quadrupole订单，并带有庞大的$ x $ x^2 y-x^2 y-type， $ z $ -Type电偶极订单，带交错的$ 3Z^2-R^2 $ -Type Antiferroquadrupole结构。我们表明，不同的奇数多极订单导致NMR中不同场依赖的光谱分布，而只有$ xy $ type的电动环形四极杆序显示NQR光谱分裂。我们还提出了可能在低能晶体场水平上激活的所有奇数多极订单的可能依赖sublattice依赖性的光谱分裂，这对于通过NQR和NMR测量值鉴定CECOSI中的奇数顺序参数非常有用。
We theoretically study NQR and NMR spectra in the presence of odd-parity multipoles originating from staggered antiferromagnetic and antiferroquadrupole orderings. For the $f$-electron metal, CeCoSi, which is a candidate hosting odd-parity multipoles, we derive an effective hyperfine field acting on Co nucleus generated from electronic origin multipole moments at Ce ion under zero and nonzero magnetic fields. We elucidate that emergent odd-parity multipoles give rise to sublattice-dependent spectral splittings in NQR and NMR through the effective hyperfine coupling in the absence of the global inversion symmetry. We mainly examine behaviors of the NQR and NMR spectra in three odd-parity multipole ordered states: a $y$-type magnetic toroidal dipole order with a staggered $x$-type antiferromagnetic structure, an $xy$-type electric toroidal quadrupole order with a staggered $x^2-y^2$-type antiferroquadrupole structure, and a $z$-type electric dipole order with a staggered $3z^2-r^2$-type antiferroquadrupole structure. We show that different odd-parity multipole orders lead to different field-dependent spectral splittings in NMR, while only the $xy$-type electric toroidal quadrupole order exhibits the NQR spectral splitting. We also present possible sublattice-dependent spectral splittings for all the odd-parity multipole orders potentially activated in low-energy crystal-field levels, which will be useful to identify odd-parity order parameters in CeCoSi by NQR and NMR measurements.
