  We apply the biorthonormal transfer-matrix renormalization group (BTMRG)
[Phys. Rev. E 83, 036702 (2011)] to study low-temperature properties of quantum
spin chains. Simulation on isotropic Heisenberg spin-1/2 chain demonstrates
that the BTMRG outperforms the conventional transfer-matrix renormalization
group (TMRG) by successfully accessing far lower temperature unreachable by
conventional TMRG, while retaining the same level of accuracy. The power of the
method is further illustrated by the calculation of the low-temperature
specific heat for a frustrated spin chain.
