arXiv subjects

S. Matsubara

Publications and source records attributed to S. Matsubara.

3 recordsLinked to original sources

arXiv2008

NMR evidence for the persistence of spin-superlattice above the 1/8 magnetization plateau in SrCu2(BO3)2

We present 11B NMR studies of the 2D frustrated dimer spin system SrCu2(BO3)2 in the field range 27-31 T covering the upper phase boundary of the 1/8 magnetization plateau, identified at 28.4 T. Our data provide a clear evidence that above 28.4 T the spin-superlattice of the 1/8 plateau is modified but does not melt even though the magnetization increases. Although this is precisely what is expected for a supersolid phase, the microscopic nature of this new phase is much more complex. We discuss the field-temperature phase diagram on the basis of our NMR data.

cond-mat.str-el↗

arXiv2005

Effects of Randomness on the Field-Induced Phase Transition in the S=1 Bond-Alternating Spin Chain NTENP

We report novel effects of randomness in the S=1 bond-alternating antiferromagnetic chain compound with a dimer-singlet ground state [Ni(N,N'-bis(3-aminopropyl)propane-1,3-diamine(mu-NO2]ClO4 abbreviated as NTENP. The 15N NMR spectra develop a continuum with sharply peaked edges at low temperatures, indicating an inhomogeneous staggered magnetization induced by magnetic field. We attribute this to random anisotropic interactions due to disorder of NO2 groups in the chains. The field-induced antiferromagnetic transition exhibits remarkably anisotropic behavior. We propose that a field-induced incoherent magnetization is transformed into a coherent antiferromagnetic moment with spatially fluctuating amplitude.

cond-mat.str-el↗

arXiv1998

Stokes Theorem for Loop Variables of Non-Abelian Gauge Field

A simple analytic proof of the formula known as the non-Abelian Stokes theorem is given. It is explicitly shown that the consistency of the formula is guaranteed by the Bianchi identity for the gauge field. An attempt is made to construct the Lagrangian for the gauge field in terms of loop variables.

hep-th↗