Proposal for a [111] magnetization plateau in the spin liquid state of Tb(2)Ti(2)O(7).

Despite a Curie-Weiss temperature θ(CW)∼-14 K, the Tb(2)Ti(2)O(7) pyrochlore magnetic material lacks long range magnetic order down to at least T(*)≈50 mK. It has recently been proposed that the low temperature collective paramagnetic or spin liquid regime of this material may be akin to a spin ice state subject to both thermal and quantum fluctuations-a quantum spin ice (QSI) of sorts. Here we explore the effect of a magnetic field B along the [111] direction on the QSI state. To do so, we investigate the magnetic properties of a microscopic model of Tb(2)Ti(2)O(7) in an independent tetrahedron approximation in a finite field B along [111]. Such a model describes semi-quantitatively the collective paramagnetic regime where nontrivial spin correlations start to develop at the shortest length scale, that is over a single tetrahedron, but where no long range order is yet present. Our results show that a magnetization plateau develops at low temperatures as the system develops B = 0 ferromagnetic spin ice like 'two-in/two-out' correlations at the shortest length scale. From these results, we are led to propose that the observation of such a [111] magnetization plateau in Tb(2)Ti(2)O(7) would provide compelling evidence for a QSI at B = 0 in this material and help guide the development of a theory for the origin of its spin liquid state.