Dynamical Structure Factors of the Spin-1/2 XXZ Chain with Inverse-Square Exchange and Ising Anisotropy

概要

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The dynarnical properties of the S : 172 anti['errounagnetic XXZ chain are sttrdied by theexact diagonalization and the rectrrsion naethod of finite systenas Lip to 24 sites. Two typesof the exchange interaction are considered: one is the nearest-neighbor type, ;rnd the otheris the inverse-sqvrare one. As the Ising anisotropy becounes larger, there appears a noticeabledifference in the transverse couaaponent S"(q, ;) lcetween the two types of the exchange. For thenearest-neighbor type, the peak freqtreracy of S"(q,cv) for each q ;tpproaches the center of' thecontintrum spectrtrrn. On flue contrary, the peak f'reqtrency for the inverse-sqtnatre type naoves tothe upper edge of the continavrvxxn, and separates I'rom the contintruna for the anisotropy largerthan the threshold value. Whether the interaction between doraaain walls (solitons) is absent orreptnlsive in the Ising Iirzait leads to this difference in the behavior of' .5" (q, w). In the longitudinalcortaponent .5" ( q, ;), on the other hand, the feature of the dynatt?ics is scarcely difl'erent betweenthe two types. The energy gap arrd the static properties are also discvrssed.
社団法人日本物理学会の論文
1998-04-15