Effect of chain conformation in the phonon transport across a Si-polyethylene single-molecule covalent junction

We use nonequilibrium molecular dynamics simulations to study heat transfer across molecular junctions formed by alkane chains covalently bonded to crystalline silicon leads. We focus our studies on the role of chain conformation on phonon transport across junctions and along the chain. We find that in the case of straight chains, all trans conformations, the silicon-polyethylene junction conductance is 180 pW/K, and heat flows ballistically, i.e. with no resistance, along the chain. The introduction of gauche conformations (kinks) leads to a nonzero thermal resistance of the chain and also reduces the junction conductance to 100 pW/K. The chain thermal resistance is proportional to the number of gauche conformations indicating that they act as strong and independent phonon scattering centers. We attribute the 80% enhancement in junction conductance during extension from coiled to straight chain conformation to ballistic (coherent) phonon transport along a straight chain.

[1]  Ming Hu,et al.  Phonon interference at self-assembled monolayer interfaces: Molecular dynamics simulations , 2010 .

[2]  Bambi Hu,et al.  T-shaped molecular heat pump , 2010, 1111.0724.

[3]  A. Henry,et al.  Anomalous heat conduction in polyethylene chains: Theory and molecular dynamics simulations , 2009 .

[4]  Ming Hu,et al.  Kapitza conductance of silicon–amorphous polyethylene interfaces by molecular dynamics simulations , 2009 .

[5]  Gang Chen,et al.  High thermal conductivity of single polyethylene chains using molecular dynamics simulations. , 2008, Physical review letters.

[6]  Arun Majumdar,et al.  Thermal conductance of thin silicon nanowires. , 2008, Physical review letters.

[7]  Baowen Li,et al.  Thermal rectification at silicon-amorphous polyethylene interface , 2008 .

[8]  J. A. Carter,et al.  Ultrafast Flash Thermal Conductance of Molecular Chains , 2007, Science.

[9]  S. Phillpot,et al.  Vibrations and thermal transport in nanocrystalline silicon , 2006 .

[10]  A. Majumdar,et al.  Room temperature thermal conductance of alkanedithiol self-assembled monolayers , 2006 .

[11]  Paul V Braun,et al.  Thermal conductance of hydrophilic and hydrophobic interfaces. , 2006, Physical review letters.

[12]  Ravi Prasher,et al.  Predicting the thermal resistance of nanosized constrictions. , 2005, Nano letters.

[13]  A. Nitzan,et al.  Molecular heat pump. , 2005, Physical review. E, Statistical, nonlinear, and soft matter physics.

[14]  N. Bernstein,et al.  Vibrational spectroscopy of an amorphous∕crystalline sandwich structure for silicon: Numerical results , 2004 .

[15]  A. Nitzan,et al.  Spin-boson thermal rectifier. , 2004, Physical review letters.

[16]  Mehdi Asheghi,et al.  Phonon–boundary scattering in ultrathin single-crystal silicon layers , 2004 .

[17]  Jian-Sheng Wang,et al.  Mode-coupling theory and molecular dynamics simulation for heat conduction in a chain with transverse motions. , 2004, Physical review. E, Statistical, nonlinear, and soft matter physics.

[18]  A. Nitzan,et al.  Thermal conductance through molecular wires , 2003, physics/0306187.

[19]  A. Politi,et al.  Universality of anomalous one-dimensional heat conductivity. , 2003, Physical review. E, Statistical, nonlinear, and soft matter physics.

[20]  S. Phillpot,et al.  Comparison of atomic-level simulation methods for computing thermal conductivity , 2002 .

[21]  G. Tsironis,et al.  Heat conduction in one-dimensional systems with hard-point interparticle interactions. , 2002, Physical review letters.

[22]  Yukihiro Tanaka,et al.  Phonon group velocity and thermal conduction in superlattices , 1999 .

[23]  M. Radny,et al.  A modified Stillinger-Weber potential for modelling silicon surfaces , 1996 .

[24]  Allen,et al.  Thermal conductivity of disordered harmonic solids. , 1993, Physical review. B, Condensed matter.

[25]  Allen,et al.  Thermal conductivity and localization in glasses: Numerical study of a model of amorphous silicon. , 1993, Physical review. B, Condensed matter.

[26]  Morgan Gj,et al.  Thermal conductivity of a single polymer chain. , 1987 .

[27]  Weber,et al.  Computer simulation of local order in condensed phases of silicon. , 1985, Physical review. B, Condensed matter.

[28]  W. Saslow,et al.  One-dimensional Kapitza conductance: Comparison of the phonon mismatch theory with computer experiments , 1978 .

[29]  S. Ulam,et al.  Studies of nonlinear problems i , 1955 .