When electrons are restricted to move in one dimension, their behavior can no longer be described by the Fermi Liquid model. In 1d, there is no energy cost for the spin carrier and charge carrier to be separated. Therefore, rather than one collective excitation carrying both spin and charge, two separate quasiparticles emerge: the spinon carrying spin, and the holon carrying charge. This new state of matter is known as the Luttinger liquid state. This state has been well described by theorists, but Luttinger liquid behavior has not been confirmed in any real system.
We hope to not only observe Luttinger liquid behavior, but also take transport measurements as a material transitions into the Luttinger liquid state. We can achieve this using Li_0.9 Mo_6 O_17, which has a structure characterized by zig-zag chains of molybdenum and oxygen atoms running along its b-axis. Electrons move easily along these chains but there is very little inter-chain hopping. Therefore, lithium molybdate is a quasi-1d conductor. By applying strain to lithium molybdate, we should be able to raise and lower the inter-chain hopping element. This would effectively tune its dimensionality, allowing us to observe a crossover from 2d to 1d behavior.